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>
diff --git a/configs/tbs2910_defconfig b/configs/tbs2910_defconfig
index 5944437..20de590 100644
--- a/configs/tbs2910_defconfig
+++ b/configs/tbs2910_defconfig
@@ -24,7 +24,7 @@
 CONFIG_USE_BOOTCOMMAND=y
 CONFIG_BOOTCOMMAND="mmc rescan; if run bootcmd_up1; then run bootcmd_up2; else run bootcmd_mmc || run distro_bootcmd; fi"
 CONFIG_USE_PREBOOT=y
-CONFIG_PREBOOT="echo PCI:; pci enum; pci 1; usb start; if hdmidet; then run set_con_hdmi; else run set_con_serial; fi"
+CONFIG_PREBOOT="echo PCI:; pci enum; pci 1; usb start"
 CONFIG_DEFAULT_FDT_FILE="imx6q-tbs2910.dtb"
 CONFIG_PRE_CONSOLE_BUFFER=y
 CONFIG_HUSH_PARSER=y
@@ -89,6 +89,7 @@
 CONFIG_DM_RTC=y
 CONFIG_RTC_DS1307=y
 CONFIG_DM_SERIAL=y
+CONFIG_SERIAL_RX_BUFFER=y
 CONFIG_MXC_UART=y
 CONFIG_DM_THERMAL=y
 CONFIG_IMX_THERMAL=y