ab8500-fg: Use correct battery charge full design

If battery is not identified while fg probe, mah_max_design gets
initialized with unknown battery's charge full design. Reinitialize
mah_max_design if battery is identified after fg probe.

Signed-off-by: Rajkumar Kasirajan <rajkumar.kasirajan@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Vijaya Kumar K-1 <vijay.kilari@stericsson.com>
Reviewed-by: Marcus COOPER <marcus.xm.cooper@stericsson.com>
Reviewed-by: Olivier CLERGEAUD <olivier.clergeaud@stericsson.com>
Reviewed-by: Arun MURTHY <arun.murthy@stericsson.com>
Reviewed-by: Rabin VINCENT <rabin.vincent@stericsson.com>
Tested-by: Rupesh KUMAR <rupesh.kumar@stericsson.com>
Tested-by: Jonas ABERG <jonas.aberg@stericsson.com>