asahi: Enable 2xMSAA (for deqp)

This also just works, let's enable it (still gated on deqp).

Signed-off-by: Asahi Lina <lina@asahilina.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22891>

src/gallium/drivers/asahi/agx_pipe.c

@@ -1817,7 +1817,8 @@ agx_is_format_supported(struct pipe_screen *pscreen, enum pipe_format format,
 
    bool is_deqp = agx_device(pscreen)->debug & AGX_DBG_DEQP;
 
-   if (sample_count > 1 && !(sample_count == 4 && is_deqp))
+   if (sample_count > 1 &&
+       (!is_deqp || (sample_count != 4 && sample_count != 2)))
       return false;
 
    if (MAX2(sample_count, 1) != MAX2(storage_sample_count, 1))