riscv: add ISA extension parsing for Zihintntl

Add parsing for Zihintntl ISA extension[1] that was ratified in commit
0dc91f5 ("Zihintntl is ratified") of riscv-isa-manual[2].

Link: https://drive.google.com/file/d/13_wsN8YmRfH8YWysFyTX-DjTkCnBd9hj/view [1]
Link: https://github.com/riscv/riscv-isa-manual/commit/0dc91f505e6d [2]
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Link: https://lore.kernel.org/r/20231114141256.126749-13-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/include/asm/hwcap.h

@@ -80,6 +80,7 @@
 #define RISCV_ISA_EXT_ZVKT		65
 #define RISCV_ISA_EXT_ZFH		66
 #define RISCV_ISA_EXT_ZFHMIN		67
+#define RISCV_ISA_EXT_ZIHINTNTL		68
 
 #define RISCV_ISA_EXT_MAX		128
 #define RISCV_ISA_EXT_INVALID		U32_MAX

arch/riscv/kernel/cpufeature.c

@@ -256,6 +256,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND),
 	__RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR),
 	__RISCV_ISA_EXT_DATA(zifencei, RISCV_ISA_EXT_ZIFENCEI),
+	__RISCV_ISA_EXT_DATA(zihintntl, RISCV_ISA_EXT_ZIHINTNTL),
 	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
 	__RISCV_ISA_EXT_DATA(zihpm, RISCV_ISA_EXT_ZIHPM),
 	__RISCV_ISA_EXT_DATA(zfh, RISCV_ISA_EXT_ZFH),