Since the VIC was converted to use generic IRQ domains IRQ 0
is silently ignored. This IRQ is used on the U300 so we're
missing it now. Bump all IRQ numbers by one since they are
now decoupled from the hardware IRQ numbers.

Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>