pd: hoho: de-assert PD_SBU_ENABLE at boot.
pd: hoho: de-assert PD_SBU_ENABLE at boot.

Per alternate mode this GPIO should not be enabled until alternate
mode has been successfully entered.

BRANCH=none
BUG=chrome-os-partner:31192
TEST=manual, compile & boot on hoho gpioget PD_SBU_ENABLE = 0

Change-Id: Ide2a47851f30812b289221e302a930134a58a8a0
Signed-off-by: Todd Broch <035f5b1f817cbb94019cec357b99778115602b63@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/223159
Reviewed-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

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