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/M5249EVB_defconfig b/configs/M5249EVB_defconfig
index 8856cd3..9e77119 100644
--- a/configs/M5249EVB_defconfig
+++ b/configs/M5249EVB_defconfig
@@ -7,6 +7,7 @@
 CONFIG_TARGET_M5249EVB=y
 CONFIG_MCFTMR=y
 CONFIG_SYS_LOAD_ADDR=0x200000
+CONFIG_SYS_MONITOR_BASE=0xFFE00400
 # CONFIG_AUTOBOOT is not set
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_SYS_DEVICE_NULLDEV=y