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/xilinx/zynq/cmds.c b/board/xilinx/zynq/cmds.c
index 1098466..0c46de7 100644
--- a/board/xilinx/zynq/cmds.c
+++ b/board/xilinx/zynq/cmds.c
@@ -10,6 +10,7 @@
 #include <asm/arch/hardware.h>
 #include <asm/arch/sys_proto.h>
 #include <malloc.h>
+#include <linux/bitops.h>
 #include <u-boot/md5.h>
 #include <u-boot/rsa.h>
 #include <u-boot/rsa-mod-exp.h>