common: Drop linux/bitops.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/seeed/linkit-smart-7688/board.c b/board/seeed/linkit-smart-7688/board.c
index 492530e..bf7c69e 100644
--- a/board/seeed/linkit-smart-7688/board.c
+++ b/board/seeed/linkit-smart-7688/board.c
@@ -6,6 +6,7 @@
 #include <common.h>
 #include <init.h>
 #include <asm/io.h>
+#include <linux/bitops.h>
 
 #define MT76XX_GPIO1_MODE	0x10000060