irqchip: armada-370-xp: implement the ->check_device() msi_chip operation

Until now, we were leaving the ->check_device() msi_chip operation
empty, which leads the PCI core to believe that we support both MSI
and MSI-X. In fact, we do not support MSI-X, so we have to tell this
to the PCI core by providing an implementation of this operation.

Fixes: 31f614ed

 ('irqchip: armada-370-xp: implement MSI support')
Cc: <stable@vger.kernel.org> # v3.13+
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1397823593-1932-3-git-send-email-thomas.petazzoni@free-electrons.com
Tested-by: Neil Greatorex <neil@fatboyfat.co.uk>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>