MIPS: move CONFIG_STANDALONE_LOAD_ADDR to CPU config makefiles

Prepare for upcoming MIPS64 CPU support.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/arch/mips/cpu/mips32/config.mk b/arch/mips/cpu/mips32/config.mk
index a0e4de5..481e984 100644
--- a/arch/mips/cpu/mips32/config.mk
+++ b/arch/mips/cpu/mips32/config.mk
@@ -30,3 +30,5 @@
 MIPSFLAGS := -march=mips32r2
 
 PLATFORM_CPPFLAGS += $(MIPSFLAGS)
+
+CONFIG_STANDALONE_LOAD_ADDR ?= 0x80200000 -T mips.lds