drm/i915/fb: Fix rounding error in subsampled plane size calculation

For NV12 FBs with odd main surface tile-row height the CCS surface
height was incorrectly calculated 1 less than the actual value. Fix this
by rounding up the result of divison. For consistency do the same for
the CCS surface width calculation.

Fixes: b3e57bcc ("drm/i915/tgl: Gen-12 render decompression")
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211026225105.2783797-2-imre.deak@intel.com

drivers/gpu/drm/i915/display/intel_fb.c

@@ -822,8 +822,8 @@ static void intel_fb_plane_dims(const struct intel_framebuffer *fb, int color_pl
 	intel_fb_plane_get_subsampling(&main_hsub, &main_vsub, &fb->base, main_plane);
 	intel_fb_plane_get_subsampling(&hsub, &vsub, &fb->base, color_plane);
 
-	*w = main_width / main_hsub / hsub;
-	*h = main_height / main_vsub / vsub;
+	*w = DIV_ROUND_UP(main_width, main_hsub * hsub);
+	*h = DIV_ROUND_UP(main_height, main_vsub * vsub);
 }
 
 static u32 intel_adjust_tile_offset(int *x, int *y,