wsi: Fixes passing argument 1 of ‘mtx_unlock’ from incompatible pointer type

wsi: Fixes passing argument 1 of ‘mtx_unlock’ from incompatible pointer type

../../src/vulkan/wsi/wsi_common_display.c:2908:15: error: passing argument 1 of ‘mtx_unlock’ from incompatible pointer type [-Werror=incompatible-pointer-types]
 2908 |    mtx_unlock(&wsi->wait_mutex);
      |               ^~~~~~~~~~~~~~~~
      |               |
      |               pthread_mutex_t *

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Acked-by: David Heidelberg <david.heidelberg@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23733>