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/cmd/mem.c b/cmd/mem.c
index 4d88254..9b97f7b 100644
--- a/cmd/mem.c
+++ b/cmd/mem.c
@@ -23,6 +23,7 @@
 #include <rand.h>
 #include <watchdog.h>
 #include <asm/io.h>
+#include <linux/bitops.h>
 #include <linux/compiler.h>
 #include <linux/delay.h>