drm/i915: s/sg_mask/sg_page_sizes/

It's a little unclear what the sg_mask actually is, so prefer the more
meaningful name of sg_page_sizes.

Suggested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171009110024.29114-1-matthew.auld@intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 41e16e1..c36a84b 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -405,7 +405,7 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj,
 {
 	unsigned int max_segment = i915_sg_segment_size();
 	struct sg_table *st;
-	unsigned int sg_mask;
+	unsigned int sg_page_sizes;
 	int ret;
 
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
@@ -435,9 +435,9 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj,
 		return ERR_PTR(ret);
 	}
 
-	sg_mask = i915_sg_page_sizes(st->sgl);
+	sg_page_sizes = i915_sg_page_sizes(st->sgl);
 
-	__i915_gem_object_set_pages(obj, st, sg_mask);
+	__i915_gem_object_set_pages(obj, st, sg_page_sizes);
 
 	return st;
 }