video: tegra: dc: Fix several coverity defects

Below is the full list of CIDs and brief explanation for each:

CID 32021: Dereference before NULL check in tegra_fb_register
CID 37876: Division or modulo by zero in tegra_dsi_get_shift_clk_div
CID 38601: Dereference after NULL check in _tegra_dc_controller_disable
CID 38907: Structurally dead code, in tegra_dc_is_powered

Bug 200192413
TDS-1898

Change-Id: I48f104c5fee497e18652786d6b3e4bdec23eb1b0
Reviewed-on: http://git-master/r/1320802
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/video/tegra/dc/dsi.c b/drivers/video/tegra/dc/dsi.c
index 071abe2ad..801a998f4 100644
--- a/drivers/video/tegra/dc/dsi.c
+++ b/drivers/video/tegra/dc/dsi.c
@@ -611,6 +611,8 @@ static struct tegra_dc_shift_clk_div tegra_dsi_get_shift_clk_div(
          * holds the real value of shift_clk_div.
          */
         shift_clk_div = dsi->default_shift_clk_div;
+        if (WARN(!shift_clk_div.div, "shift_clk_div.div is 0\n"))
+                return shift_clk_div;
 
         /* Calculate shift_clk_div which can match the video_burst_mode. */
         if (dsi->info.video_burst_mode >=