board: tbs2910: Add serial rx buffer in defconfig

... to avoid loosing characters when pasting text into the serial console.
This allows to remove the workaround to disable the vidconsole output
when no HDMI device is detected. This workaround only was there to speed-up
serial console processing.

Signed-off-by: Soeren Moch <smoch@web.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
2 files changed