sh: mach-se: Fix up SE7206 build.

With some recent tidying of duplicate register definitions the se7206 IRQ
code broke:

arch/sh/boards/mach-se/7206/irq.c: error: 'INTC_ICR' undeclared (first use in this function)
arch/sh/boards/mach-se/7206/irq.c: error: (Each undeclared identifier is reported only once
arch/sh/boards/mach-se/7206/irq.c: error: for each function it appears in.)

Fix it up.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>