stm32mon supports read unprotection.
stm32mon supports read unprotection.

Details please refer to AN3155 document.

BUG=None
TEST=run on real machine.
% stm32mon -U
% stm32mon -u
% stm32mon -w new_image

Change-Id: I070e18a7cb112afe0ab0d0f0bd06cecc4eefb37e
Signed-off-by: Louis Yung-Chieh Lo <2d80bee8408e64f859a1b5868bd3b311c0a4b4cd@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/27630
Reviewed-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Tested-by: Yung-Chieh Lo <0191079b79ddcfdff3dcfd37feb08dc3a3d76395@gtempaccount.com>
Commit-Ready: Yung-Chieh Lo <0191079b79ddcfdff3dcfd37feb08dc3a3d76395@gtempaccount.com>

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