ARM: 7395/1: VIC: use the domain mapping function to assign handlers

This removes the internal functions for assigning IRQ
handlers to each interrupt in favor of using the internal
map iterator in the irq domain code.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>