radv: allow clear merging for depth/stencil with no care stencil

radv: allow clear merging for depth/stencil with no care stencil

Some of the Sascha Willems demos pick a D32/S8 format for the depth
buffer, then do a LOAD_OP_CLEAR/LOAD_OP_DONT_CARE on it, which means
we don't get to merge the undefined->depth and clear htile transitions.

This add the stencil aspect to the pending clears if there is a depth
clear pending and the stencil aspect is don't care.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Signed-off-by: Dave Airlie <airlied@redhat.com>