power_supply: tosa_battery: Get rid of irq_to_gpio usage

This commit fixes the following error:

 linux/drivers/power/tosa_battery.c:153:2: error: implicit declaration of
 function 'irq_to_gpio' [-Werror=implicit-function-declaration]

Since 9d08d5d7, irq_to_gpio() is no longer
available but still in use by collie_battery.c. As it's just for a debug
message, just get rid of this call.

Signed-off-by: Andrea Adami <andrea.adami@gmail.com>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>