Fix a bug causing TMP006 debug message truncated.
Fix a bug causing TMP006 debug message truncated.

The debug message is larger than UART transmit buffer so we have to
flush the output manually.

Signed-off-by: Vic Yang <victoryang@chromium.org>

BUG=chrome-os-partner:8265
TEST='tmp006' shows debug message of all TMP006 sensors.

Change-Id: I81793504e1a345b172567d3e877ee8740b85640c

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