mpt3sas_get_port_by_id() can be called when a spinlock is held. Use
GFP_ATOMIC instead of GFP_KERNEL when allocating memory.

Issue spotted by call_kern.cocci:
./drivers/scsi/mpt3sas/mpt3sas_scsih.c:416:42-52: ERROR: function mpt3sas_get_port_by_id called on line 7125 inside lock on line 7123 but uses GFP_KERNEL
./drivers/scsi/mpt3sas/mpt3sas_scsih.c:416:42-52: ERROR: function mpt3sas_get_port_by_id called on line 6842 inside lock on line 6839 but uses GFP_KERNEL
./drivers/scsi/mpt3sas/mpt3sas_scsih.c:416:42-52: ERROR: function mpt3sas_get_port_by_id called on line 6854 inside lock on line 6851 but uses GFP_KERNEL
./drivers/scsi/mpt3sas/mpt3sas_scsih.c:416:42-52: ERROR: function mpt3sas_get_port_by_id called on line 7706 inside lock on line 7702 but uses GFP_KERNEL
./drivers/scsi/mpt3sas/mpt3sas_scsih.c:416:42-52: ERROR: function mpt3sas_get_port_by_id called on line 10260 inside lock on line 10256 but uses GFP_KERNEL

Link: https://lore.kernel.org/r/20210220093951.905362-1-christophe.jaillet@wanadoo.fr
Fixes: 324c122f ("scsi: mpt3sas: Add module parameter multipath_on_hba")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>