powerpc: mpc83xx: Migrate DEFAULT_IMMR to Kconfig

As no platforms override this value, set it for all mpc83xx platforms.

Cc: Mario Six <mario.six@gdsys.cc>
Cc: Wolfgang Denk <wd@denx.de>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/powerpc/cpu/mpc83xx/Kconfig b/arch/powerpc/cpu/mpc83xx/Kconfig
index 2ebf8fc..d1b9ae4 100644
--- a/arch/powerpc/cpu/mpc83xx/Kconfig
+++ b/arch/powerpc/cpu/mpc83xx/Kconfig
@@ -1,6 +1,10 @@
 menu "mpc83xx CPU"
 	depends on MPC83xx
 
+config DEFAULT_IMMR
+	hex
+	default 0xFF400000
+
 config E300
 	def_bool y