sh: Reinstate ILSEL -> IRL intc mappings for SH-X3 proto CPU.

In the multi-evt conversion for the SH-X3 proto CPU, IRLs were dropped
down to a single unique masking source, which ended up blowing up on
ILSEL-based IRQs which have special semantics that otherwise confuse the
intc code. While this does result in intc spewing about not having a
unique masking source, we don't really care.

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