ARM: opcodes: add missing include of linux/linkage.h

opcodes.h wants to declare an asmlinkage function, so we need to include
linux/linkage.h
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NDave Martin <dave.martin@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm/include/asm/opcodes.h

@@ -10,6 +10,7 @@
 #define __ASM_ARM_OPCODES_H
 
 #ifndef __ASSEMBLY__
+#include <linux/linkage.h>
 extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr);
 #endif