util/disk_cache: check for write() failure in the zstd path

CoverityID: 1458074
Fixes: a8d941091f72923561a6 ("util: Use ZSTD for shader cache if possible")
Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3672>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3672>
1 file changed