Kbuild: add LDFLAGS_STANDALONE

Introduce a new Makefile variable for passing LDFLAGS to standalone
programs. Currently the variable CONFIG_STANDALONE_LOAD_ADDR is
misued on some archs to pass a specific linker script.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/arch/riscv/config.mk b/arch/riscv/config.mk
index ed9eb0c..cc5d8d1 100644
--- a/arch/riscv/config.mk
+++ b/arch/riscv/config.mk
@@ -27,8 +27,8 @@
 EFI_LDS			:= elf_riscv64_efi.lds
 endif
 
-CONFIG_STANDALONE_LOAD_ADDR = 0x00000000 \
-			      -T $(srctree)/examples/standalone/riscv.lds
+CONFIG_STANDALONE_LOAD_ADDR = 0x00000000
+LDFLAGS_STANDALONE += -T $(srctree)/examples/standalone/riscv.lds
 
 PLATFORM_CPPFLAGS	+= -ffixed-gp -fpic
 PLATFORM_RELFLAGS	+= -fno-common -gdwarf-2 -ffunction-sections