windcharger: enable gpio4 on reset to maintain poe

GPIO4 is hardwired to output CPU_CLK/4 immediately after reset, and by the time
we set the state in ath_gpio_config the PoE devices have already rebooted.
Instead we configure GPIO4 as early as possible so that PoE devices won't be
interrupted. This way the power interruption is approximately 440uS which can
be safely tolerated by GFLT devices.

PVT boards will use a different GPIO for PoE control, and this fix won't be
needed.

Change-Id: Id96566b86c917a25d45cd295efb6549a955135fd
3 files changed