Remove __ARM_ARCH__ guard on gcm_*_v8.

OpenSSL's c1669e1c20 switched it to
__ARM_MAX_ARCH__, which we mirrored in assembly but not C. The C version
should be __ARM_MAX_ARCH__ to match. However, __ARM_MAX_ARCH__ is
hardcoded to 8, so just remove the check.

Change-Id: Ic873203db1478f49437b889b84ee7fb28eba1a6d
Reviewed-on: https://boringssl-review.googlesource.com/c/35045
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>

crypto/fipsmodule/modes/internal.h

@@ -315,8 +315,6 @@ void gcm_ghash_4bit_mmx(uint64_t Xi[2], const u128 Htable[16], const uint8_t *in
 #endif  // OPENSSL_X86
 
 #elif defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64)
-#include <openssl/arm_arch.h>
-#if __ARM_ARCH__ >= 7
 #define GHASH_ASM_ARM
 #define GCM_FUNCREF_4BIT
 
@@ -352,7 +350,6 @@ OPENSSL_INLINE void gcm_ghash_neon(uint64_t Xi[2], const u128 Htable[16],
 }
 #endif  // OPENSSL_ARM
 
-#endif  // __ARM_ARCH__ >= 7
 #elif defined(OPENSSL_PPC64LE)
 #define GHASH_ASM_PPC64LE
 #define GCM_FUNCREF_4BIT