panfrost: Z16 depth buffer support

Only for MFBD GPUs as on t720 it causes some dEQP tests to fail.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7201>
diff --git a/src/panfrost/lib/pan_format.c b/src/panfrost/lib/pan_format.c
index 7aae980..b133442 100644
--- a/src/panfrost/lib/pan_format.c
+++ b/src/panfrost/lib/pan_format.c
@@ -155,6 +155,7 @@
 
         [PIPE_FORMAT_R3G3B2_UNORM] 		= { MALI_RGB332_UNORM, _VT },
 
+        [PIPE_FORMAT_Z16_UNORM]                 = { MALI_R16_UNORM, _TZ },
         [PIPE_FORMAT_Z24_UNORM_S8_UINT]		= { MALI_Z24X8_UNORM, _TZ },
         [PIPE_FORMAT_Z24X8_UNORM]		= { MALI_Z24X8_UNORM, _TZ },
         [PIPE_FORMAT_Z32_FLOAT]		        = { MALI_R32F, _TZ },