scsi: smartpqi: call pqi_free_interrupts() in pqi_shutdown()

scsi: smartpqi: call pqi_free_interrupts() in pqi_shutdown()

We must free all irqs during shutdown, else kexec's 2nd kernel would hang
in pqi_wait_for_completion_io() as below:

Call trace:

 pqi_wait_for_completion_io
 pqi_submit_raid_request_synchronous.constprop.78+0x23c/0x310 [smartpqi]
 pqi_configure_events+0xec/0x1f8 [smartpqi]
 pqi_ctrl_init+0x814/0xca0 [smartpqi]
 pqi_pci_probe+0x400/0x46c [smartpqi]
 local_pci_probe+0x48/0xb0
 pci_device_probe+0x14c/0x1b0
 really_probe+0x218/0x3fc
 driver_probe_device+0x70/0x140
 __driver_attach+0x11c/0x134
 bus_for_each_dev+0x70/0xc8
 driver_attach+0x30/0x38
 bus_add_driver+0x1f0/0x294
 driver_register+0x74/0x12c
 __pci_register_driver+0x64/0x70
 pqi_init+0xd0/0x10000 [smartpqi]
 do_one_initcall+0x60/0x1d8
 do_init_module+0x64/0x1f8
 load_module+0x10ec/0x1350
 __se_sys_finit_module+0xd4/0x100
 __arm64_sys_finit_module+0x28/0x34
 el0_svc_handler+0x104/0x160
 el0_svc+0x8/0xc

This happens only in the following combinations:

1. smartpqi is built as module, not built-in;
2. We have a disk connected to smartpqi card;
3. Both kexec's 1st and 2nd kernels use this disk as Rootfs' mount point.

Signed-off-by: Yanjiang Jin <yanjiang.jin@hxt-semitech.com>
Acked-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>