arm64: constify aarch64_insn_encoding_class[]

The aarch64_insn_encoding_class[] array contains compile-time constant
data, and is never intentionally modified, so let's mark it as const.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NWill Deacon <will@kernel.org>

arch/arm64/kernel/insn.c

@@ -26,7 +26,7 @@
 #define AARCH64_INSN_N_BIT	BIT(22)
 #define AARCH64_INSN_LSL_12	BIT(22)
 
-static int aarch64_insn_encoding_class[] = {
+static const int aarch64_insn_encoding_class[] = {
 	AARCH64_INSN_CLS_UNKNOWN,
 	AARCH64_INSN_CLS_UNKNOWN,
 	AARCH64_INSN_CLS_UNKNOWN,