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>

drivers/gpu/drm/i915/intel_sprite.c

@@ -1034,7 +1034,7 @@ intel_plane_init(struct drm_device *dev, enum pipe pipe, int plane)
 	if (INTEL_INFO(dev)->gen < 5)
 		return -ENODEV;
 
-	intel_plane = kzalloc(sizeof(struct intel_plane), GFP_KERNEL);
+	intel_plane = kzalloc(sizeof(*intel_plane), GFP_KERNEL);
 	if (!intel_plane)
 		return -ENOMEM;