Blackfin: use common code to preprocess linker script

Now that the common code preprocesses the linker script, the Blackfin code
no longer needs to do it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/lib_blackfin/config.mk b/lib_blackfin/config.mk
index 0dd2ac6..a7e3658 100644
--- a/lib_blackfin/config.mk
+++ b/lib_blackfin/config.mk
@@ -62,5 +62,5 @@
 LDR_FLAGS += $(LDR_FLAGS-y)
 
 ifeq ($(wildcard $(TOPDIR)/board/$(BOARD)/u-boot.lds*),)
-LDSCRIPT = $(obj)lib_$(ARCH)/u-boot.lds
+LDSCRIPT = $(obj)lib_$(ARCH)/u-boot.lds.S
 endif