Move most of irqs.h so it can be used as #include "irqs.h"
instead of the old style #include <mach/irqs.h>.

Legacy code in drivers/pinctrl needs more work to get rid
of the "mach" portion of the include path, so some part
is left in the original location.
Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
[horms+renesas@verge.net.au: Do not add trailing blank line to irqs.h]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>