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/M5235EVB_Flash32_defconfig b/configs/M5235EVB_Flash32_defconfig
index f0077b6..7383978 100644
--- a/configs/M5235EVB_Flash32_defconfig
+++ b/configs/M5235EVB_Flash32_defconfig
@@ -8,6 +8,7 @@
 CONFIG_NORFLASH_PS32BIT=y
 CONFIG_MCFTMR=y
 CONFIG_SYS_LOAD_ADDR=0x20000
+CONFIG_SYS_MONITOR_BASE=0xFFC00400
 CONFIG_BOOTDELAY=1
 # CONFIG_DISPLAY_BOARDINFO is not set
 # CONFIG_CMDLINE_EDITING is not set