pm2301-charger: lpn pin used only in C2C boards

This patch restricts use of LPN pin to C2C boards to avoid
conflict on HSI for GPIO 60 use.

Signed-off-by: Benoit GAUTHIER <benoit.gauthier-xsig@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Mustapha BEN-ZOUBEIR <mustapha.ben.zoubeir-xsig@stericsson.com>
Reviewed-by: Philippe LANGLAIS <philippe.langlais@stericsson.com>
Tested-by: Benoit GAUTHIER <benoit.gauthier-xsig@stericsson.com>