drm/i915: use pointer = k[cmz...]alloc(sizeof(*pointer), ...) pattern

Done while reviewing all our allocations for fubar. Also a few errant
cases of lacking () for the sizeof operator - just a bit of OCD.

I've left out all the conversions that also should use kcalloc from
this patch  (it's only 2).

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index 8d6d0a1..a98a990 100644
--- a/drivers/gpu/drm/i915/intel_overlay.c
+++ b/drivers/gpu/drm/i915/intel_overlay.c
@@ -1053,7 +1053,7 @@
 		return ret;
 	}
 
-	params = kmalloc(sizeof(struct put_image_params), GFP_KERNEL);
+	params = kmalloc(sizeof(*params), GFP_KERNEL);
 	if (!params)
 		return -ENOMEM;
 
@@ -1320,7 +1320,7 @@
 	if (!HAS_OVERLAY(dev))
 		return;
 
-	overlay = kzalloc(sizeof(struct intel_overlay), GFP_KERNEL);
+	overlay = kzalloc(sizeof(*overlay), GFP_KERNEL);
 	if (!overlay)
 		return;