push LOAD_ADDR out to arch mk files

Rather than maintain/extend the current ifeq($(ARCH)) mess that exists in
the standalone Makefile, push the setting up of LOAD_ADDR out to the arch
config.mk (and rename to STANDALONE_LOAD_ADDR in the process).  This keeps
the common code clean and lets the arch do whatever crazy crap it wants in
its own area.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/lib_ppc/config.mk b/lib_ppc/config.mk
index d91ef7f..010d874 100644
--- a/lib_ppc/config.mk
+++ b/lib_ppc/config.mk
@@ -23,6 +23,8 @@
 
 CROSS_COMPILE ?= ppc_8xx-
 
+STANDALONE_LOAD_ADDR = 0x40000
+
 PLATFORM_CPPFLAGS += -DCONFIG_PPC -D__powerpc__
 PLATFORM_LDFLAGS  += -n