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/pwm/rk_pwm.c b/drivers/pwm/rk_pwm.c
index 66eb0e7..911da1d 100644
--- a/drivers/pwm/rk_pwm.c
+++ b/drivers/pwm/rk_pwm.c
@@ -14,6 +14,7 @@
 #include <syscon.h>
 #include <asm/io.h>
 #include <asm/arch-rockchip/pwm.h>
+#include <linux/bitops.h>
 #include <power/regulator.h>
 
 DECLARE_GLOBAL_DATA_PTR;