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/ls1021aqds_ddr4_nor_defconfig b/configs/ls1021aqds_ddr4_nor_defconfig
index a232c73..7c49471 100644
--- a/configs/ls1021aqds_ddr4_nor_defconfig
+++ b/configs/ls1021aqds_ddr4_nor_defconfig
@@ -1,14 +1,16 @@
 CONFIG_ARM=y
 CONFIG_TARGET_LS1021AQDS=y
+CONFIG_SYS_FSL_DDR4=y
 CONFIG_VIDEO=y
 CONFIG_DEFAULT_DEVICE_TREE="ls1021a-qds-duart"
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_OF_STDOUT_VIA_ALIAS=y
-CONFIG_SYS_FSL_DDR4=y
 CONFIG_BOOTDELAY=3
 CONFIG_SILENT_CONSOLE=y
+# CONFIG_CONSOLE_MUX is not set
+CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_BOOTZ=y
 CONFIG_CMD_GREPENV=y