gpio-rcar: R-Car GPIO IRQ share interrupt

R-Car H1 or Gen2 GPIO interrupts are assigned per each GPIO domain,
but, Gen1 E1/M1 GPIO interrupts are shared for all GPIO domain.
gpio-rcar driver needs IRQF_SHARED flags for these.
This patch was tested on Bock-W board

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>