ARM: 6057/1: Realview: register PMU IRQs during board initialisation

This patch updates the initialisation routines for the Realview boards
and the Versatile Express board [ca9x4 tile] so that they register their
PMU IRQs with the PMU framework in the Kernel.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>