flash_ec: Add support for kunimitsu, kunimitsu_pd, and strago_pd
flash_ec: Add support for kunimitsu, kunimitsu_pd, and strago_pd

BUG=none
TEST=Verified EC and PD is able to flash on kunimitsu and strago
BRANCH=none

Change-Id: I31b9ed57d4cd7a1c09cedbf9c873e76770abd3c8
Signed-off-by: Kevin K Wong <8bf1d1ccd36a6bfde85ceaaa1fe52f2093ecf3aa@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/282000
Reviewed-by: Shawn N <5259333ce42e3ace6a73988cec7115ed9d3a661a@chromium.org>

coreboot/chrome-ec,fourier49/BZ_DEV_EC,coreboot/chrome-ec,fourier49/BIZ_EC,akappy7/ChromeOS_EC_LED_Diagnostics,md5555/ec,fourier49/BZ_DEV_EC,coreboot/chrome-ec,fourier49/BIZ_EC,fourier49/BZ_DEV_EC,fourier49/BIZ_EC,fourier49/BIZ_EC,md5555/ec,md5555/ec,coreboot/chrome-ec,coreboot/chrome-ec,md5555/ec,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,fourier49/BZ_DEV_EC,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics