riscv: errata: prefix T-Head mnemonics with th.

T-Head now maintains some specification for their extended instructions
at [1], in which all instructions are prefixed "th.".

Follow this practice in the kernel comments.

Link: https://github.com/T-head-Semi/thead-extension-spec [1]
Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Author: Icenowy

arch/riscv/include/asm/errata_list.h

@@ -95,25 +95,25 @@ asm volatile(ALTERNATIVE(						\
 #endif
 
 /*
- * dcache.ipa rs1 (invalidate, physical address)
+ * th.dcache.ipa rs1 (invalidate, physical address)
  * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
  *   0000001    01010      rs1       000      00000  0001011
- * dache.iva rs1 (invalida, virtual address)
+ * th.dache.iva rs1 (invalida, virtual address)
  *   0000001    00110      rs1       000      00000  0001011
  *
- * dcache.cpa rs1 (clean, physical address)
+ * th.dcache.cpa rs1 (clean, physical address)
  * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
  *   0000001    01001      rs1       000      00000  0001011
- * dcache.cva rs1 (clean, virtual address)
+ * th.dcache.cva rs1 (clean, virtual address)
  *   0000001    00101      rs1       000      00000  0001011
  *
- * dcache.cipa rs1 (clean then invalidate, physical address)
+ * th.dcache.cipa rs1 (clean then invalidate, physical address)
  * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
  *   0000001    01011      rs1       000      00000  0001011
- * dcache.civa rs1 (... virtual address)
+ * th.dcache.civa rs1 (... virtual address)
  *   0000001    00111      rs1       000      00000  0001011
  *
- * sync.s (make sure all cache operations finished)
+ * th.sync.s (make sure all cache operations finished)
  * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
  *   0000000    11001     00000      000      00000  0001011
  */