sna: Validate framebuffer tiling before creation

In sna_pixmap_alloc_gpu() a different than the default tiling may be picked
by a usage hint. Before passing the tiling to kgem_create_2d() fix it up
by calling kgem_choose_tiling(). This avoids kgem_surface_size() not being able
to find a surface size for the tiling value.

Fixes regression from

commit a10781b70f [2.99.913]
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Jul 1 15:11:07 2014 +0100

    sna: Enforce LinearFramebuffer option

Signed-off-by: Egbert Eich <eich@freedesktop.org>

src/sna/sna_accel.c

@@ -1617,7 +1617,11 @@ static bool sna_pixmap_alloc_gpu(struct sna *sna,
 	/* Use tiling by default, but disable per user request */
 	if (pixmap->usage_hint == SNA_CREATE_FB && (sna->flags & SNA_LINEAR_FB) == 0) {
 		flags |= CREATE_SCANOUT;
-		tiling = -I915_TILING_X;
+		tiling = kgem_choose_tiling(&sna->kgem,
+					    -I915_TILING_X,
+					    pixmap->drawable.width,
+					    pixmap->drawable.height,
+					    pixmap->drawable.bitsPerPixel);
 	} else
 		tiling = sna_pixmap_default_tiling(sna, pixmap);