Blackfin: unify u-boot linker scripts

All the Blackfin linker scripts were duplicated across the board dirs with
no difference save from the semi-often used ENV_IS_EMBEDDED option.  So
unify all of them in the lib_blackfin/ dir and for the few boards that
need to embedded the environment directly, add a LDS_BOARD_TEXT define for
them to customize via their board config file.  This is much simpler than
forcing them to duplicate the rest of the linker script.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/lib_blackfin/Makefile b/lib_blackfin/Makefile
index 46ef7f3..e32ecc9 100644
--- a/lib_blackfin/Makefile
+++ b/lib_blackfin/Makefile
@@ -47,9 +47,12 @@
 SRCS	:= $(SOBJS-y:.o=.S) $(COBJS-y:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS-y) $(COBJS-y))
 
-$(LIB):	$(obj).depend $(OBJS)
+$(LIB):	$(obj).depend $(OBJS) $(obj)u-boot.lds
 	$(AR) $(ARFLAGS) $@ $(OBJS)
 
+$(obj)u-boot.lds: u-boot.lds.S
+	$(CPP) $(CPPFLAGS) -D__ASSEMBLY__ -P $^ > $@
+
 #########################################################################
 
 # defines $(obj).depend target