scsi: target: core: Use RCU helpers for INQUIRY t10_alua_tg_pt_gp

scsi: target: core: Use RCU helpers for INQUIRY t10_alua_tg_pt_gp

Fix the sparse warnings about t10_alua_tg_pt_gp accesses in
target_core_spc.c caused by commit 70c71a8923e6 ("scsi: target: Replace
lun_tg_pt_gp_lock with rcu in I/O path")

That commit replaced the lun_tg_pt_gp_lock use in the I/O path, but it
didn't update the INQUIRY code.

Link: https://lore.kernel.org/r/20211117213928.8634-1-michael.christie@oracle.com
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>