ARM: mach-shmobile: sh7372 INTCS MFIS2 interrupt update

Enable the MFIS2 interrupt source in the INTCS interrupt
controller included in the sh7372 processor. The priority
field is constantly enabled to let the interrupt through to
both the ARM side and the SH side.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>