panfrost: Handle PIPE_FORMAT_S8_UINT

For wallpaper blits with separate stencil.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5827>
diff --git a/src/panfrost/encoder/pan_format.c b/src/panfrost/encoder/pan_format.c
index d7b0b20..67c6fba 100644
--- a/src/panfrost/encoder/pan_format.c
+++ b/src/panfrost/encoder/pan_format.c
@@ -141,6 +141,7 @@
         [PIPE_FORMAT_Z32_FLOAT]		        = { MALI_R32F, _TZ },
         [PIPE_FORMAT_Z32_FLOAT_S8X24_UINT]	= { MALI_R32F, _TZ },
         [PIPE_FORMAT_X24S8_UINT]		= { MALI_RGBA8UI, _TZ },
+        [PIPE_FORMAT_S8_UINT]   		= { MALI_R8UI, _T },
 
         [PIPE_FORMAT_R32_FIXED] 		= { MALI_R32_FIXED, _V },
         [PIPE_FORMAT_R32G32_FIXED] 		= { MALI_RG32_FIXED, _V },