usb/xhci: unify parameter of xhci_msi_irq

According to Felipe and Alan's comments the second parameter of irq
handler should be 'void *' not a specific structure pointer.
So change it.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>