sparc64: This patch adds PRIQ support.

sparc64: This patch adds PRIQ support.

This patch supports INT_A through INT_D interrupts as described
by the Open Firmware device tree as well as MSI vectors registered
by PCIe drivers. pci=nomsi may not work though frankly that makes no
sense on a SPARC machine.

The command line parameter priq=off reverts to prior MSIEQ interrupt
mechanism.

OraBug: 22748924

Signed-off-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: Chris Hyser <chris.hyser@oracle.com>
(cherry picked from commit d4c668861f91dfe6f5fa1a809218a8c46dc76c9b)
(cherry picked from commit c47c2d2a53856b25843e07c78f42f45a17661d2c)
Signed-off-by: Allen Pais <allen.pais@oracle.com>