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/eb_cpu5282_internal_defconfig b/configs/eb_cpu5282_internal_defconfig
index 7e865d8..7dcbe6c 100644
--- a/configs/eb_cpu5282_internal_defconfig
+++ b/configs/eb_cpu5282_internal_defconfig
@@ -4,6 +4,7 @@
 CONFIG_SYS_TEXT_BASE=0xF0000000
 CONFIG_SYS_EXTRA_OPTIONS="SYS_MONITOR_BASE=0xF0000418"
 CONFIG_BOOTDELAY=5
+# CONFIG_CONSOLE_MUX is not set
 # CONFIG_DISPLAY_BOARDINFO is not set
 # CONFIG_CMD_LOADB is not set
 CONFIG_CMD_I2C=y