drm/udl: fix line iterator in damage handling

The udl damage handler is supposed to render 'height' lines, but its
iterator has an obvious typo that makes it miss most lines if the
rectangle does not cover 0/0.

Fix the damage handler to correctly render all lines.

This is a fallout from:

    commit e375882
    Author: Noralf Trønnes <[email protected]>
    Date:   Thu Apr 28 17:18:37 2016 +0200

        drm/udl: Use drm_fb_helper deferred_io support

Tested-by: poma <[email protected]>
Cc: [email protected] # 4.7+
Reviewed-by: Daniel Vetter <[email protected]>
Signed-off-by: David Herrmann <[email protected]>
Reviewed-by: Eric Engestrom <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>

Author: David Herrmann

drivers/gpu/drm/udl/udl_fb.c

@@ -122,7 +122,7 @@ int udl_handle_damage(struct udl_framebuffer *fb, int x, int y,
 		return 0;
 	cmd = urb->transfer_buffer;
 
-	for (i = y; i < height ; i++) {
+	for (i = y; i < y + height ; i++) {
 		const int line_offset = fb->base.pitches[0] * i;
 		const int byte_offset = line_offset + (x * bpp);
 		const int dev_byte_offset = (fb->base.width * bpp * i) + (x * bpp);