sh: extend INTC with struct intc_hw_desc

This patch updates the INTC code by moving all vectors,
groups and registers from struct intc_desc to struct
intc_hw_desc.

The idea is that INTC tables should go from using the
macro(s) DECLARE_INTC_DESC..() only to using struct
intc_desc with name and hw initialized using the macro
INTC_HW_DESC(). This move makes it easy to initialize
an extended struct intc_desc in the future.

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