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/drivers/mtd/nand/core.c b/drivers/mtd/nand/core.c
index bc0accf..6fbd24b 100644
--- a/drivers/mtd/nand/core.c
+++ b/drivers/mtd/nand/core.c
@@ -14,6 +14,7 @@
 #include <linux/compat.h>
 #include <linux/module.h>
 #endif
+#include <linux/bitops.h>
 #include <linux/mtd/nand.h>
 
 /**