radv: flush DB cache before and after HTILE decompress.

radv: flush DB cache before and after HTILE decompress.

It reads @ writes the DB cache, and we haven't flushed dst caches yet,
so DB cache may be stale. Also the user might be shader read (and probably is),
so also flush after.

Signed-off-by: Bas Nieuwenhuizen <basni@google.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
CC: <mesa-stable@lists.freedesktop.org>
Fixes: f4e499ec791 ("radv: add initial non-conformant radv vulkan driver")
(cherry picked from commit a8c51b1cd9168b621e27cf5308d0dd8fc08f8a4a)
[Andres Gomez: resolve trivial conflicts]
Signed-off-by: Andres Gomez <agomez@igalia.com>
Conflicts:
	src/amd/vulkan/radv_cmd_buffer.c