irqchip: mips-gic: Share register writes in gic_set_type()

irqchip: mips-gic: Share register writes in gic_set_type()

The gic_set_type() function included writes to the MIPS GIC polarity,
trigger & dual-trigger registers in each case of a switch statement
determining the IRQs type. This is all well & good when we only have a
single cluster & thus a single GIC whose register we want to update. It
will lead to significant duplication once we have multi-cluster support
& multiple GICs to update.

Refactor this such that we determine values for the polarity, trigger &
dual-trigger registers and then have a single set of register writes
following the switch statement. This will allow us to write the same
values to each GIC in a multi-cluster system in a later patch, rather
than needing to duplicate more register writes in each case.

Signed-off-by: Paul Burton <[email protected]>
Cc: Jason Cooper <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Marc Zyngier <[email protected]>