Introduce a new linker flag LDFLAGS_FINAL

commit 8aba9dceebb14144e07d19593111ee3a999c37fc
Divides variable of linker flags to LDFLAGS-u-boot and LDFLAGS

breaks the usage of --gc-section to build nand_spl. We still need linker option
--gc-section for every uboot image, not only the main one. LDFLAGS_FINAL passes
the --gc-sections to each uboot image.

To get the proper linker flags, we use LDFLAGS and LDFLAGS_FINAL to replace
PLATFORM_LDFLAGS in the Makefile of each nand_spl board.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Haiying Wang <Haiying.Wang@freescale.com>
diff --git a/arch/i386/config.mk b/arch/i386/config.mk
index a84af63..67aac0d 100644
--- a/arch/i386/config.mk
+++ b/arch/i386/config.mk
@@ -38,6 +38,6 @@
 
 PLATFORM_LDFLAGS += --emit-relocs -Bsymbolic -Bsymbolic-functions
 
-LDFLAGS_u-boot += --gc-sections -pie
+LDFLAGS_FINAL += --gc-sections -pie
 LDSCRIPT := $(SRCTREE)/$(CPUDIR)/u-boot.lds