ARM: 7300/1: realview: fix definition of GPIO0 interrupt on PB1176 to match TRM

Currently, -1 is used as the GPIO0 interrupt on realview PB1176 and an
AMBA device is registered with this parameter. With the pending NO_IRQ
cleanup, this will lead to a warning at boot time, since -1 is obviously
broken.

This patch updates the interrupt used for GPIO0 to match that specified
by the TRM. Unfortunately, it's not clear how to trigger this interrupt
so we trust that the documentation is correct.

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