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/include/bitfield.h b/include/bitfield.h
index 579a69c..d3ceeed 100644
--- a/include/bitfield.h
+++ b/include/bitfield.h
@@ -36,6 +36,7 @@
  * tables which describe all bitfields in all registers.
  */
 
+#include <linux/bitops.h>
 #include <linux/types.h>
 
 /* Produces a mask of set bits covering a range of a uint value */