gpu: nvgpu: gk20a: Use NULL instead of integer '0'

Fixed the following sparse warning by using the proper 'NULL' instead of '0':
- fifo_gk20a.c: warning: Using plain integer as NULL pointer

Bug 200067946
Bug 200088648

Change-Id: I316b119e87b7203450ce85232398b43384ee16cc
Signed-off-by: Amit Sharma (SW-TEGRA) <amisharma@nvidia.com>
Reviewed-on: http://git-master/r/755348
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-by: Sachin Nikam <snikam@nvidia.com>
Reviewed-on: http://git-master/r/757050

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
index 4ef310b2..731074de 100644
--- a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
@@ -946,7 +946,7 @@ static bool gk20a_fifo_handle_mmu_fault(
                 struct fifo_mmu_fault_info_gk20a f;
                 struct channel_gk20a *ch = NULL;
                 struct tsg_gk20a *tsg = NULL;
-                struct channel_gk20a *referenced_channel = 0;
+                struct channel_gk20a *referenced_channel = NULL;
                 /* read and parse engine status */
                 u32 status = gk20a_readl(g, fifo_engine_status_r(engine_id));
                 u32 ctx_status = fifo_engine_status_ctx_status_v(status);