Convert SILENT_CONSOLE options to Kconfig

Move these option to Kconfig and tidy up existing uses.

The Power PC boards don't have a suitable common element: the common header
files don't appear to line up with the Kconfig files as far as I can tell.
This results in a lot of defconfig changes.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jteki@openedev.com>
[trini: Re-migrate, update common/console.c logic]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/T1042RDB_PI_SDCARD_defconfig b/configs/T1042RDB_PI_SDCARD_defconfig
index fd5da57..1894c62 100644
--- a/configs/T1042RDB_PI_SDCARD_defconfig
+++ b/configs/T1042RDB_PI_SDCARD_defconfig
@@ -14,6 +14,7 @@
 CONFIG_OF_STDOUT_VIA_ALIAS=y
 CONFIG_SYS_EXTRA_OPTIONS="PPC_T1042,T1042RDB_PI,RAMBOOT_PBL,SPL_FSL_PBL,SDCARD"
 CONFIG_BOOTDELAY=10
+CONFIG_SILENT_CONSOLE=y
 CONFIG_SPL=y
 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT=y
 CONFIG_HUSH_PARSER=y