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/rng/rockchip_rng.c b/drivers/rng/rockchip_rng.c
index 47fb140..c6a834b 100644
--- a/drivers/rng/rockchip_rng.c
+++ b/drivers/rng/rockchip_rng.c
@@ -6,6 +6,7 @@
 #include <asm/io.h>
 #include <common.h>
 #include <dm.h>
+#include <linux/bitops.h>
 #include <linux/iopoll.h>
 #include <linux/string.h>
 #include <rng.h>