kernel/irq.c contains a comment that speaks of -1 and -2 as interrupt
numbers, but this is actually dependent on configuration options now.
Replace by NO_IRQ and NO_IRQ_ENABLED.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>