Add comxtest debug command
Add comxtest debug command

Remove dummy boot-time output to UART1; no longer needed now that
there's a debug command to do the same thing.

Signed-off-by: Randall Spangler <rspangler@chromium.org>

BUG=none
TEST=manual
comxtest - prints default message to x86 UART
comxtext ccc123 - prints 'ccc123' to x86 UART

Change-Id: I37d37aeca06bf71b106f5ad3473a79780fd089a9

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