Convert CONFIG_SYS_CONSOLE_IS_IN_ENV and CONFIG_CONSOLE_MUX to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_CONSOLE_IS_IN_ENV
   CONFIG_CONSOLE_MUX

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Re-order, re-migrate]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/tbs2910_defconfig b/configs/tbs2910_defconfig
index e86b781..07c161e 100644
--- a/configs/tbs2910_defconfig
+++ b/configs/tbs2910_defconfig
@@ -2,10 +2,10 @@
 CONFIG_ARCH_MX6=y
 CONFIG_TARGET_TBS2910=y
 CONFIG_PRE_CONSOLE_BUFFER=y
-CONFIG_PRE_CON_BUF_ADDR=0x7c000000
 CONFIG_VIDEO=y
 CONFIG_FIT=y
 CONFIG_BOOTDELAY=3
+CONFIG_PRE_CON_BUF_ADDR=0x7c000000
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="Matrix U-Boot> "
 CONFIG_CMD_BOOTZ=y