radeonsi: fix encryption check for buffers

The writable bit means read-write, not just write.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Fixes: 8873ea0e25 ("radeonsi: determine secure flag must be set for gfx IB")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11107>

src/gallium/drivers/radeonsi/si_descriptors.c

@@ -1033,9 +1033,7 @@ static bool si_buffer_resources_check_encrypted(struct si_context *sctx,
    while (mask) {
       int i = u_bit_scan64(&mask);
 
-      /* only check for reads */
-      if ((buffers->writable_mask & (1llu << i)) == 0 &&
-          (si_resource(buffers->buffers[i])->flags & RADEON_FLAG_ENCRYPTED))
+      if (si_resource(buffers->buffers[i])->flags & RADEON_FLAG_ENCRYPTED)
          return true;
    }