Make flash_ec capable of writing to an incorrectly-protected STM32
Make flash_ec capable of writing to an incorrectly-protected STM32

If EC-RO protects itself via the WRPx option bytes, flash_ec will fail
to reprogram it.  And if EC-RO is broken/unbootable, it won't be able
to clear the WRPx option bytes itself when it sees the write protect
GPIO is not asserted.

Add the -u flag to stm32mon so that it will automatically attempt to
unprotect the flash via the option bytes.

BUG=chrome-os-partner:19723
BRANCH=none
TEST=enable write protect GPIO.  Then from console, 'flashwp enable'.
     Then from the chroot:
        ./util/flash_ec --board=pit --ro --image=build/pit/ec.RO.flat
     That should successfully reflash the board.

Change-Id: Ic356d29104294d04d5e2a36dc75fd0206b89bd34
Signed-off-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/56659

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