RISCV: one last little nit to make it build and run

Change-Id: I6e9e1dff09c08079774f7d6e60e67a12760d37b4
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: http://review.coreboot.org/7645
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
diff --git a/src/arch/riscv/Makefile.inc b/src/arch/riscv/Makefile.inc
index 1020fc7..242fd40 100644
--- a/src/arch/riscv/Makefile.inc
+++ b/src/arch/riscv/Makefile.inc
@@ -41,7 +41,9 @@
 
 $(objcbfs)/bootblock.debug: $(src)/arch/riscv/bootblock.ld $(obj)/ldoptions $$(bootblock-objs)
 	@printf "    LINK       $(subst $(obj)/,,$(@))\n"
-	$(LD_bootblock) -m elf64lriscv --gc-sections -static -o $@ -L$(obj) $< -T $(src)/arch/riscv/bootblock.ld
+	$(CC_bootblock) $(CFLAGS_bootblock) -nostartfiles -Wl,--gc-sections -static -o $@ -L$(obj) \
+		-T $(src)/arch/riscv/bootblock.ld -Wl,--start-group $(bootblock-objs) \
+		$(LIBGCC_FILE_NAME_bootblock) -Wl,--end-group
 
 endif