drm/msm: Fix null pointer dereference on pointer edp

The initialization of pointer dev dereferences pointer edp before
edp is null checked, so there is a potential null pointer deference
issue. Fix this by only dereferencing edp after edp has been null
checked.

Addresses-Coverity: ("Dereference before null check")
Fixes: ab5b0107 ("drm/msm: Initial add eDP support in msm drm driver (v5)")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20210929121857.213922-1-colin.king@canonical.comSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/edp/edp_ctrl.c

@@ -1116,7 +1116,7 @@ void msm_edp_ctrl_power(struct edp_ctrl *ctrl, bool on)
 int msm_edp_ctrl_init(struct msm_edp *edp)
 {
 	struct edp_ctrl *ctrl = NULL;
-	struct device *dev = &edp->pdev->dev;
+	struct device *dev;
 	int ret;
 
 	if (!edp) {
@@ -1124,6 +1124,7 @@ int msm_edp_ctrl_init(struct msm_edp *edp)
 		return -EINVAL;
 	}
 
+	dev = &edp->pdev->dev;
 	ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
 	if (!ctrl)
 		return -ENOMEM;