sh-pfc: sh7372: Replace <mach/irqs.h> with <linux/sh_intc.h>

The mach/irqs.h header is included only to get the evt2irq macro
definition. The macro is defined in linux/sh_intc.h, include it directly
instead of the mach-specific header.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Magnus Damm <damm@opensource.se>