qla2xxx: Fix crash due to null pointer access

qla2xxx: Fix crash due to null pointer access

commit fc1ffd6cb38a1c1af625b9833c41928039e733f5 upstream.

During code inspection, while investigating following stack trace
seen on one of the test setup, we found out there was possibility
of memory leak becuase driver was not unwinding the stack properly.

This issue has not been reproduced in a test environment or on a
customer setup.

Here's stack trace that was seen.

[1469877.797315] Call Trace:
[1469877.799940]  [<ffffffffa03ab6e9>] qla2x00_mem_alloc+0xb09/0x10c0 [qla2xxx]
[1469877.806980]  [<ffffffffa03ac50a>] qla2x00_probe_one+0x86a/0x1b50 [qla2xxx]
[1469877.814013]  [<ffffffff813b6d01>] ? __pm_runtime_resume+0x51/0xa0
[1469877.820265]  [<ffffffff8157c1f5>] ? _raw_spin_lock_irqsave+0x25/0x90
[1469877.826776]  [<ffffffff8157cd2d>] ? _raw_spin_unlock_irqrestore+0x6d/0x80
[1469877.833720]  [<ffffffff810741d1>] ? preempt_count_sub+0xb1/0x100
[1469877.839885]  [<ffffffff8157cd0c>] ? _raw_spin_unlock_irqrestore+0x4c/0x80
[1469877.846830]  [<ffffffff81319b9c>] local_pci_probe+0x4c/0xb0
[1469877.852562]  [<ffffffff810741d1>] ? preempt_count_sub+0xb1/0x100
[1469877.858727]  [<ffffffff81319c89>] pci_call_probe+0x89/0xb0

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[ bvanassche: Fixed spelling in patch description ]
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>