docs/LoongArch: Fix notes rendering by using reST directives

Notes are better expressed with reST admonitions.

Fixes: 0ea8ce6 ("Documentation: LoongArch: Add basic documentations")
Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: Yanteng Si

Documentation/loongarch/introduction.rst

@@ -45,10 +45,12 @@ Name              Alias           Usage               Preserved
 ``$r23``-``$r31`` ``$s0``-``$s8`` Static registers    Yes
 ================= =============== =================== ============
 
-Note: The register ``$r21`` is reserved in the ELF psABI, but used by the Linux
-kernel for storing the percpu base address. It normally has no ABI name, but is
-called ``$u0`` in the kernel. You may also see ``$v0`` or ``$v1`` in some old code,
-however they are deprecated aliases of ``$a0`` and ``$a1`` respectively.
+.. Note::
+    The register ``$r21`` is reserved in the ELF psABI, but used by the Linux
+    kernel for storing the percpu base address. It normally has no ABI name,
+    but is called ``$u0`` in the kernel. You may also see ``$v0`` or ``$v1``
+    in some old code,however they are deprecated aliases of ``$a0`` and ``$a1``
+    respectively.
 
 FPRs
 ----
@@ -69,8 +71,9 @@ Name              Alias              Usage               Preserved
 ``$f24``-``$f31`` ``$fs0``-``$fs7``  Static registers    Yes
 ================= ================== =================== ============
 
-Note: You may see ``$fv0`` or ``$fv1`` in some old code, however they are deprecated
-aliases of ``$fa0`` and ``$fa1`` respectively.
+.. Note::
+    You may see ``$fv0`` or ``$fv1`` in some old code, however they are
+    deprecated aliases of ``$fa0`` and ``$fa1`` respectively.
 
 VRs
 ----

Documentation/loongarch/irq-chip-model.rst

@@ -145,12 +145,16 @@ Documentation of Loongson's LS7A chipset:
 
   https://github.com/loongson/LoongArch-Documentation/releases/latest/download/Loongson-7A1000-usermanual-2.00-EN.pdf (in English)
 
-Note: CPUINTC is CSR.ECFG/CSR.ESTAT and its interrupt controller described
-in Section 7.4 of "LoongArch Reference Manual, Vol 1"; LIOINTC is "Legacy I/O
-Interrupts" described in Section 11.1 of "Loongson 3A5000 Processor Reference
-Manual"; EIOINTC is "Extended I/O Interrupts" described in Section 11.2 of
-"Loongson 3A5000 Processor Reference Manual"; HTVECINTC is "HyperTransport
-Interrupts" described in Section 14.3 of "Loongson 3A5000 Processor Reference
-Manual"; PCH-PIC/PCH-MSI is "Interrupt Controller" described in Section 5 of
-"Loongson 7A1000 Bridge User Manual"; PCH-LPC is "LPC Interrupts" described in
-Section 24.3 of "Loongson 7A1000 Bridge User Manual".
+.. Note::
+    - CPUINTC is CSR.ECFG/CSR.ESTAT and its interrupt controller described
+      in Section 7.4 of "LoongArch Reference Manual, Vol 1";
+    - LIOINTC is "Legacy I/OInterrupts" described in Section 11.1 of
+      "Loongson 3A5000 Processor Reference Manual";
+    - EIOINTC is "Extended I/O Interrupts" described in Section 11.2 of
+      "Loongson 3A5000 Processor Reference Manual";
+    - HTVECINTC is "HyperTransport Interrupts" described in Section 14.3 of
+      "Loongson 3A5000 Processor Reference Manual";
+    - PCH-PIC/PCH-MSI is "Interrupt Controller" described in Section 5 of
+      "Loongson 7A1000 Bridge User Manual";
+    - PCH-LPC is "LPC Interrupts" described in Section 24.3 of
+      "Loongson 7A1000 Bridge User Manual".