So what if there is a status_gpio specified? bq24735_charger_is_present()
do have a working fallback for the case of no status_gpio.

Simplify this by not special casing setups w/o status_gpio, folding
two consecutive if-blocks in the process.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Sebastian Reichel <sre@kernel.org>