msm: kgsl: Do not dereference pointer before checking against NULL

The pagetable pointer was checked against NULL after being used.
Check against NULL first and then dereference it.

Change-Id: I714de9e3b153f212cb92502a21c7d720dd4e1e37
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>
diff --git a/drivers/gpu/msm/kgsl_gpummu.c b/drivers/gpu/msm/kgsl_gpummu.c
index 942aa12..bbb5d46 100644
--- a/drivers/gpu/msm/kgsl_gpummu.c
+++ b/drivers/gpu/msm/kgsl_gpummu.c
@@ -357,8 +357,8 @@
 int kgsl_gpummu_pt_equal(struct kgsl_pagetable *pt,
 					unsigned int pt_base)
 {
-	struct kgsl_gpummu_pt *gpummu_pt = pt->priv;
-	return pt && pt_base && (gpummu_pt->base.gpuaddr == pt_base);
+	struct kgsl_gpummu_pt *gpummu_pt = pt ? pt->priv : NULL;
+	return gpummu_pt && pt_base && (gpummu_pt->base.gpuaddr == pt_base);
 }
 
 void kgsl_gpummu_destroy_pagetable(void *mmu_specific_pt)