max17042_battery: Handle irq request failure case

suspend/resume functions take action based upon the fuel gauge
interrupt. If the rquest irq fails we should assign 0 to client->irq.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>