sh: intc - fix IRQ4 and IRQ5 typo on sh3

The intc tables for sh3 currently contain a typo where the bit
fields in IPRD are mixed up for IRQ4 and IRQ5. This patch makes
sure the correct bit fields are used - all according to the
datasheets.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>