src: Remove useless comments in "includes" lines

Change-Id: Ide5673dc99688422c5078c8c28ca5935fd39c854
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50186
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/arch/arm/include/armv7/arch/mmio.h

@@ -7,7 +7,7 @@
 #ifndef __ARCH_MMIO_H__
 #define __ARCH_MMIO_H__
 
-#include <arch/cache.h>		/* for dmb() */
+#include <arch/cache.h>
 #include <endian.h>
 #include <stdint.h>