arm64: cpufeature: constify arm64_ftr_bits structures

The arm64_ftr_bits structures are never modified, so make them read-only.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 7099f26..7c0b7cf 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -72,11 +72,11 @@
  * @sys_val		Safe value across the CPUs (system view)
  */
 struct arm64_ftr_reg {
-	u32			sys_id;
-	const char		*name;
-	u64			strict_mask;
-	u64			sys_val;
-	struct arm64_ftr_bits	*ftr_bits;
+	u32				sys_id;
+	const char			*name;
+	u64				strict_mask;
+	u64				sys_val;
+	const struct arm64_ftr_bits	*ftr_bits;
 };
 
 /* scope of capability check */
@@ -157,7 +157,7 @@
 	return cpuid_feature_extract_unsigned_field_width(features, field, 4);
 }
 
-static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)
+static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp)
 {
 	return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);
 }
@@ -170,7 +170,7 @@
 		cpuid_feature_extract_unsigned_field(features, field);
 }
 
-static inline s64 arm64_ftr_value(struct arm64_ftr_bits *ftrp, u64 val)
+static inline s64 arm64_ftr_value(const struct arm64_ftr_bits *ftrp, u64 val)
 {
 	return (s64)cpuid_feature_extract_field(val, ftrp->shift, ftrp->sign);
 }