[PATCH] firmware: meson_sm: stop using 0 as NULL pointer

[Miles Chen]

Use NULL for NULL pointer to fix the following sparse warning:
drivers/firmware/meson/meson_sm.c:85:24: sparse: warning: Using plain integer as NULL pointer

Signed-off-by: Miles Chen <miles.chen at mediatek.com>
---
 drivers/firmware/meson/meson_sm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c
index 77aa5c6398aa..3f5ff9ed668e 100644
--- a/drivers/firmware/meson/meson_sm.c
+++ b/drivers/firmware/meson/meson_sm.c
@@ -82,7 +82,7 @@ static void __iomem *meson_sm_map_shmem(u32 cmd_shmem, unsigned int size)
 
 	sm_phy_base = __meson_sm_call(cmd_shmem, 0, 0, 0, 0, 0);
 	if (!sm_phy_base)
-		return 0;
+		return NULL;
 
 	return ioremap_cache(sm_phy_base, size);
 }
-- 
2.18.0