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/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 80bed69..09c93d7 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2156,7 +2156,7 @@
 {
 	struct drm_info_node *node;
 
-	node = kmalloc(sizeof(struct drm_info_node), GFP_KERNEL);
+	node = kmalloc(sizeof(*node), GFP_KERNEL);
 	if (node == NULL) {
 		debugfs_remove(ent);
 		return -ENOMEM;