irqchip: irq-gic: Fix checkpatch errors

Fixes the following errors:
ERROR: do not initialise statics to 0 or NULL
ERROR: space required after that ',' (ctx:VxV)

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>