irqchip/gicv3-its: Read typer register outside the loop

No need to read the typer register in the loop. Values do not change.

This patch is basically a prerequisite for a follow-on patch that adds
errata code for Cavium ThunderX. It moves the calculation of the
number of id entries to the beginning of the function close to other
setup values that are needed to allocate the its table. Now we have a
central location to modify the setup parameters and the errata code
can be implemented in a single block.

Signed-off-by: Robert Richter <rrichter@cavium.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tirumalesh Chalamarla <tchalamarla@cavium.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1442869119-1814-4-git-send-email-rric@kernel.org


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>