Divides variable of linker flags to LDFLAGS-u-boot and LDFLAGS

Linker needs to use the proper endian/bfd flags even when doing partial linking.
LDFLAGS_u-boot sets linker option which is called it when U-boot is built
(u-boot final).
LDFLAGS sets necessary option by partial linking (use in cmd_link_o_target).

CC: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/arch/blackfin/config.mk b/arch/blackfin/config.mk
index ab117ca..0cba294 100644
--- a/arch/blackfin/config.mk
+++ b/arch/blackfin/config.mk
@@ -30,7 +30,8 @@
 PLATFORM_RELFLAGS += -ffixed-P3 -fomit-frame-pointer -mno-fdpic
 PLATFORM_CPPFLAGS += -DCONFIG_BLACKFIN
 
-LDFLAGS += --gc-sections -m elf32bfin
+LDFLAGS_u-boot += --gc-sections
+LDFLAGS += -m elf32bfin
 PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections
 
 PLATFORM_CPPFLAGS += -DBFIN_CPU='"$(CONFIG_BFIN_CPU)"'