radeonsi: use unreachable to fix a warning

si_state.c: In function ‘si_make_texture_descriptor’:
si_state.c:3240:25: warning: ‘num_format’ may be used uninitialized
si_state.c:3240:12: warning: ‘data_format’ may be used uninitialized

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>
1 file changed