gpio/pca953x: fix error handling path in probe() call

If the device fails to respond, then the error path tries to remove an
interrupt that never got registered, which causes an backtrace from the
interrupt handling code.

Fix this by ensuring that the cleanup path has two labels and use the
correct path as needed.

fixes the following error:

WARNING: at kernel/irq/manage.c:908 __free_irq+0x80/0x160()
Trying to free already-free IRQ 0

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>