arch/arm64/include/armv8/arch/barrier.h: Add spaces around colons

The linter requests spaces around colons. Add them.

Signed-off-by: Yuchen He <yuchenhe126@gmail.com>
Change-Id: I46d11666126dd8585ef7d4bab68a5b4b01fb7c29
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73748
Reviewed-by: Felix Singer <felixsinger@posteo.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/arch/arm64/include/armv8/arch/barrier.h

@@ -21,7 +21,7 @@
 #define wmb()		asm volatile("dsb st" : : : "memory")
 
 #if CONFIG(SMP)
-#define barrier() __asm__ __volatile__("": : :"memory")
+#define barrier() __asm__ __volatile__("" : : : "memory")
 #endif
 
 #define nop()		asm volatile("nop");