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/pepper_defconfig b/configs/pepper_defconfig
index a6f00c6..a13b07b 100644
--- a/configs/pepper_defconfig
+++ b/configs/pepper_defconfig
@@ -1,6 +1,5 @@
 CONFIG_ARM=y
 CONFIG_AM33XX=y
-CONFIG_TARGET_PEPPER=y
 CONFIG_SPL_GPIO_SUPPORT=y
 CONFIG_SPL_LIBCOMMON_SUPPORT=y
 CONFIG_SPL_LIBGENERIC_SUPPORT=y
@@ -11,6 +10,7 @@
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL_POWER_SUPPORT=y
 CONFIG_SPL_SERIAL_SUPPORT=y
+CONFIG_TARGET_PEPPER=y
 CONFIG_SPL_WATCHDOG_SUPPORT=y
 CONFIG_VERSION_VARIABLE=y
 CONFIG_SPL=y