scsi: mpi3mr: Fix possible crash when setting up bsg fails

If bsg_setup_queue() fails, the bsg_queue is assigned a non-NULL value.
Consequently, in mpi3mr_bsg_exit(), the condition "if(!mrioc->bsg_queue)"
will not be satisfied, preventing execution from entering
bsg_remove_queue(), which could lead to the following crash:

BUG: kernel NULL pointer dereference, address: 000000000000041c
Call Trace:
  <TASK>
  mpi3mr_bsg_exit+0x1f/0x50 [mpi3mr]
  mpi3mr_remove+0x6f/0x340 [mpi3mr]
  pci_device_remove+0x3f/0xb0
  device_release_driver_internal+0x19d/0x220
  unbind_store+0xa4/0xb0
  kernfs_fop_write_iter+0x11f/0x200
  vfs_write+0x1fc/0x3e0
  ksys_write+0x67/0xe0
  do_syscall_64+0x38/0x80
  entry_SYSCALL_64_after_hwframe+0x78/0xe2

Fixes: 4268fa75 ("scsi: mpi3mr: Add bsg device support")
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250107022032.24006-1-kanie@linux.alibaba.com


Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>