ARM: mach-shmobile: Rework sh7372 INTCS demuxer V2

This patch is the sh7372 INTC demux rework V2.

Updates the sh7372 INTCS demuxer to not hook into
the INTCA interrupt controller. The mask register
for the chained INTCS interrupt source happens
to be located in the INTCS register range instead of
the INTCA as expected. To allow each INTCA and INTCS
interrupt controller to work in their own IRQ range
this patch moves the INTCS vector away.

Needed for future IRQ domain support.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>