drm/i915: Fix vma allocator debug

Add a missing colon which I accidentally removed in the recent logging
changes.

Signed-off-by: Tvrtko Ursulin <[e-mail]>
Fixes: a10234fda466 ("drm/i915: Partial abandonment of legacy DRM logging macros")
Cc: Andrzej Hajda <[e-mail]>
Reviewed-by: Andrzej Hajda <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/i915_vma.c

···
 	char buf[512];
 
 	if (!vma->node.stack) {
-		drm_dbg(&to_i915(vma->obj->base.dev)->drm
+		drm_dbg(&to_i915(vma->obj->base.dev)->drm,
 			"vma.node [%08llx + %08llx] %s: unknown owner\n",
 			vma->node.start, vma->node.size, reason);
 		return;