arm: Don't include common.h in header files

It is bad practice to include common.h in other header files since it can
bring in any number of superfluous definitions. It implies that some C
files don't include it and thus may be missing CONFIG options that are set
up by that file. The C files should include these themselves.

Update some header files in arch/arm to drop this.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/wandboard/spl.c b/board/wandboard/spl.c
index dbd9d02..250043a 100644
--- a/board/wandboard/spl.c
+++ b/board/wandboard/spl.c
@@ -5,6 +5,7 @@
  *         Richard Hu <hakahu@gmail.com>
  */
 
+#include <common.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/arch/iomux.h>