Update mach-shmobile to use 0x3400 as INTCS_VECT_BASE.

Since the ARM architecture a little while back added support
for 10 bit irqs we can now undo the previously merged commit
9b7c23ad and use 0x3400 as
INTCS vector base.

This change is necessary to avoid overlapping of interrupt
ranges so separate IRQ domains can be used for different INTC
instances. Without this fix the vectors used by various INTC
instances are overlapping on for instance sh7372 which works
at the moment but breaks upcoming IRQ domain support.
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>