nir/lower_io_to_vector: remove can_read_output assert

Since we're not creating new output reads, just vectorizing existing
ones, this isn't the place to assert whether we can actually read
outputs.

Signed-off-by: Job Noorman <jnoorman@igalia.com>
Reviewed-by: Emma Anholt <anholt@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34784>
1 file changed