scsi: myrb: Fix up null pointer access on myrb_cleanup()

stable inclusion
from stable-v5.10.122
commit ebfe2797253f64f728855d377fdc7d136fdbcfb5
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5W6OE

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ebfe2797253f64f728855d377fdc7d136fdbcfb5

--------------------------------

[ Upstream commit f9f0a461 ]

When myrb_probe() fails the callback might not be set, so we need to
validate the 'disable_intr' callback in myrb_cleanup() to not cause a null
pointer exception. And while at it do not call myrb_cleanup() if we cannot
enable the PCI device at all.

Link: https://lore.kernel.org/r/20220523120244.99515-1-hare@suse.de


Reported-by: Zheyu Ma <zheyuma97@gmail.com>
Tested-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>