mtip32xx: Remove superfluous call to pci_disable_msi()

There is no need to call pci_disable_msi() in case
the previous call to pci_enable_msi() failed

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>