scsi: qla2xxx: Fix qla2x00_request_irqs() for MSI

scsi: qla2xxx: Fix qla2x00_request_irqs() for MSI

Commit 4fa183455988 ("scsi: qla2xxx: Utilize pci_alloc_irq_vectors/
pci_free_irq_vectors calls.") use pci_alloc_irq_vectors() to replace
pci_enable_msi() but it didn't handle the return value correctly. This bug
make qla2x00 always fail to setup MSI if MSI-X fail, so fix it.

BTW, improve the log message of return value in qla2x00_request_irqs() to
avoid confusion.

Fixes: 4fa183455988 ("scsi: qla2xxx: Utilize pci_alloc_irq_vectors/pci_free_irq_vectors calls.")
Cc: Michael Hernandez <michael.hernandez@cavium.com>
Link: https://lore.kernel.org/r/1574314847-14280-1-git-send-email-chenhc@lemote.com
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>