spring: enable USB boost charger by default
spring: enable USB boost charger by default

Needed for easy power on until we have the full USB charge state
machine.

note: the GPIO name ILIM_1500 is somewhat misleading,
it is connected to the enable pin of the TPS43060

Signed-off-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

BUG=chrome-os-partner:14319
TEST=manual :
plug the board and press servo power button,
see the AP rails coming up.

Change-Id: I93421d1581065bcc1e7be07086e74d11d1e1ec56
Reviewed-on: https://gerrit.chromium.org/gerrit/35271
Commit-Ready: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Tested-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Reviewed-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

akappy7/ChromeOS_EC_LED_Diagnostics,thehobn/ec,gelraen/cros-ec,mtk09422/chromiumos-platform-ec,longsleep/ec,coreboot/chrome-ec,thehobn/ec,mtk09422/chromiumos-platform-ec,eatbyte/chromium-ec,eatbyte/chromium-ec,fourier49/BIZ_EC,alterapraxisptyltd/chromium-ec,gelraen/cros-ec,longsleep/ec,thehobn/ec,longsleep/ec,coreboot/chrome-ec,gelraen/cros-ec,fourier49/BIZ_EC,coreboot/chrome-ec,alterapraxisptyltd/chromium-ec,fourier49/BZ_DEV_EC,alterapraxisptyltd/chromium-ec,md5555/ec,eatbyte/chromium-ec,coreboot/chrome-ec,fourier49/BZ_DEV_EC,akappy7/ChromeOS_EC_LED_Diagnostics,longsleep/ec,akappy7/ChromeOS_EC_LED_Diagnostics,eatbyte/chromium-ec,fourier49/BZ_DEV_EC,fourier49/BIZ_EC,mtk09422/chromiumos-platform-ec,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BIZ_EC,md5555/ec,coreboot/chrome-ec,fourier49/BZ_DEV_EC,gelraen/cros-ec,md5555/ec,coreboot/chrome-ec,mtk09422/chromiumos-platform-ec,thehobn/ec,md5555/ec,akappy7/ChromeOS_EC_LED_Diagnostics,alterapraxisptyltd/chromium-ec