dt-bindings: riscv: update ratified version of h, svinval, svnapot, svpbmt

The descriptions for h, svinval, svnapot, and svpbmt extensions currently
reference the "20191213 version of the privileged ISA specification".
While an Unprivileged ISA document exists with that date, there is no
corresponding ratified Privileged ISA specification.

These extensions were ratified in the RISC-V Instruction Set Manual,
Volume II: Privileged Architecture, Version 20211203. Update the
descriptions to reference the correct specification version.

RISC-V International hosts a website [1] for ratified specifications.
Following the "Ratified ISA Specifications", historical versions of
Volume II Privileged ISA can be found.

Link: https://riscv.org/specifications/ratified/ [1]
Fixes: aeb71e4 ("dt-bindings: riscv: deprecate riscv,isa")
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Guodong Xu <guodong@riscstar.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Author: docularxu

Documentation/devicetree/bindings/riscv/extensions.yaml

@@ -117,8 +117,9 @@ properties:
 
         - const: h
           description:
-            The standard H extension for hypervisors as ratified in the 20191213
-            version of the privileged ISA specification.
+            The standard H extension for hypervisors as ratified in the RISC-V
+            Instruction Set Manual, Volume II Privileged Architecture,
+            Document Version 20211203.
 
         # multi-letter extensions, sorted alphanumerically
         - const: smaia
@@ -202,20 +203,22 @@ properties:
         - const: svinval
           description:
             The standard Svinval supervisor-level extension for fine-grained
-            address-translation cache invalidation as ratified in the 20191213
-            version of the privileged ISA specification.
+            address-translation cache invalidation as ratified in the RISC-V
+            Instruction Set Manual, Volume II Privileged Architecture,
+            Document Version 20211203.
 
         - const: svnapot
           description:
             The standard Svnapot supervisor-level extensions for napot
-            translation contiguity as ratified in the 20191213 version of the
-            privileged ISA specification.
+            translation contiguity as ratified in the RISC-V Instruction Set
+            Manual, Volume II Privileged Architecture, Document Version
+            20211203.
 
         - const: svpbmt
           description:
             The standard Svpbmt supervisor-level extensions for page-based
-            memory types as ratified in the 20191213 version of the privileged
-            ISA specification.
+            memory types as ratified in the RISC-V Instruction Set Manual,
+            Volume II Privileged Architecture, Document Version 20211203.
 
         - const: svrsw60t59b
           description: