scsi: sd: Revert "Inline sd_probe_part2()"

Reverts commit d16ece57 to make a clean revert of its predecessor
possible.

Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>