sh: intc - mark data structures as __initdata

With the intc core improved it is now possible to put the intc data
structures in the initdata section.

Version two of this patch puts the __initdata inside DECLARE_INTC_DESC()
and removes the __initdata included in the board specific r2d code.

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