drm/tinydrm: Fix setting of the column/page end addresses.

If the clipped dirty region's x/y happened to align to 256, we would
have set the top 8 bits wrong.  Noticed by inspection, not by
reproducing a bug.
Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20181024184313.2967-4-eric@anholt.netReviewed-by: Noralf Trønnes <noralf@tronnes.org>

drivers/gpu/drm/tinydrm/mipi-dbi.c

@@ -240,10 +240,10 @@ static int mipi_dbi_fb_dirty(struct drm_framebuffer *fb,
 
 	mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
 			 (clip.x1 >> 8) & 0xFF, clip.x1 & 0xFF,
-			 (clip.x2 >> 8) & 0xFF, (clip.x2 - 1) & 0xFF);
+			 ((clip.x2 - 1) >> 8) & 0xFF, (clip.x2 - 1) & 0xFF);
 	mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,
 			 (clip.y1 >> 8) & 0xFF, clip.y1 & 0xFF,
-			 (clip.y2 >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);
+			 ((clip.y2 - 1) >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);
 
 	ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START, tr,
 				(clip.x2 - clip.x1) * (clip.y2 - clip.y1) * 2);