scsi: fnic: Return error if vmalloc() failed

scsi: fnic: Return error if vmalloc() failed

In fnic_init_module() exists redundant check for return value from
fnic_debugfs_init(), because at moment it only can return zero. It make
sense to process theoretical vmalloc() failure.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 9730ddfb123d ("scsi: fnic: remove redundant assignment of variable rc")
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Link: https://lore.kernel.org/r/20231128111008.2280507-1-artem.chernyshev@red-soft.ru
Reviewed-by: Karan Tilak Kumar <kartilak@cisco.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>