pf: fix error codes in pf_init_unit()

Return a negative error code instead of success on these error paths.

Fixes: fb367e6b ("pf: cleanup initialization")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20211001122654.GB2283@kili


Signed-off-by: Jens Axboe <axboe@kernel.dk>