ARM: shmobile: r8a7779: use gic_iid macro

"ARM: shmobile: add gic_iid macro for ICCIAR / interrupt ID"
enabled to use gic_iid macro.
This patch exchange current GIC interrupt setting
from gic_spi() to gic_iid()

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[ horms+renesas@verge.net.au: Updated git commit id in changelog ]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>