firefly: update VBUS voltage sensing
firefly: update VBUS voltage sensing

The voltage divider resistor values have changes to 10K/100K,
update the code to take this into account.

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

BRANCH=none
BUG=none
TEST=none

Change-Id: I2a1469e3441c4bea2bfe3f3a3b7f8ac2225cca51
Reviewed-on: https://chromium-review.googlesource.com/200343
Reviewed-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Commit-Queue: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Tested-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

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