ARM: mach-shmobile: sh73a0 and AG5EVM PINT support

Support PINT on sh73a0 and AG5EVM using INTC PINT macros.

With this patch applied the AG5EVM ethernet is handled
through one of the chained sh73a0 PINT interrupt controllers.

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