Convert CONFIG_SYS_MONITOR_BASE to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_MONITOR_BASE

Note that for how this is re-used on some PowePC platforms, we introduce
CONFIG_SPL_SYS_MONITOR_BASE and CONFIG_TPL_SYS_MONITOR_BASE and use the
CONFIG_VAL macro to get the correct value at build time, in the code.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/M5275EVB_defconfig b/configs/M5275EVB_defconfig
index 2a7b312..fe80671 100644
--- a/configs/M5275EVB_defconfig
+++ b/configs/M5275EVB_defconfig
@@ -7,6 +7,7 @@
 CONFIG_TARGET_M5275EVB=y
 CONFIG_MCFTMR=y
 CONFIG_SYS_LOAD_ADDR=0x800000
+CONFIG_SYS_MONITOR_BASE=0xFFE00400
 CONFIG_BOOTDELAY=5
 CONFIG_USE_BOOTCOMMAND=y
 CONFIG_BOOTCOMMAND="bootm ffe40000"