Remove dependency of flash_ec on crosutils
Remove dependency of flash_ec on crosutils

The script currently depends on common.sh from crosutils, which is not
installed on beaglebone and also pulls in dependency on other
repositories. Let's switch to shared shflags library and include output
formatting functions in flash_ec script. This way we are independent
from crosutils.

BUG=chromium:397202
TEST=Run the script to flash EC
BRANCH=None

Change-Id: Ib18987410eb32d773d55fb4e53133adf230167b9
Signed-off-by: Vic Yang <5fd92abeee651458f98e2856f4f200ee971cee4d@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/209827
Reviewed-by: Dan Shi <ddf10325a07dcd5610d94b7b9f19da3abc09e645@chromium.org>
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>

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