arm64: relax assembly code alignment from 16 byte to 4 byte

Aarch64 instructions must be word aligned.  The current 16 byte
alignment is more than enough.  Relax it into 4 byte alignment.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/linkage.h

 #ifndef __ASM_LINKAGE_H
 #define __ASM_LINKAGE_H
 
-#define __ALIGN		.align 4
-#define __ALIGN_STR	".align 4"
+#define __ALIGN		.align 2
+#define __ALIGN_STR	".align 2"
 
 #endif