This patch modifies the get_irqnr_preamble macro to work with multiple
platforms at run-time by reading the address of the GIC controller from
the gic_cpu_base_addr variable. This variable is defined in core.c and
intialised in realview_eb.c (gic_init_irq).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>