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/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 859f41a..e16c2f3 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -8,6 +8,7 @@
 #define _ASM_GENERIC_GPIO_H_
 
 #include <dm/ofnode.h>
+#include <linux/bitops.h>
 
 struct ofnode_phandle_args;