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/PMC440_defconfig b/configs/PMC440_defconfig
index af38882..cd2f0d2 100644
--- a/configs/PMC440_defconfig
+++ b/configs/PMC440_defconfig
@@ -3,6 +3,7 @@
 CONFIG_TARGET_PMC440=y
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_BOOTDELAY=3
+CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_VERSION_VARIABLE=y
 CONFIG_AUTOBOOT_KEYED=y
 CONFIG_AUTOBOOT_PROMPT="Press SPACE to abort autoboot in %d seconds\n"