qemu_v8.mk: add scripts_gdb kernel build target

This allows CONFIG_GDB_SCRIPTS=y to be used with optee-build
and means we can more easily debug the kernel using gdb.

CONFIG_GDB_SCRIPTS gives you python commands such as lx-dmesg
(useful for hangs before any serial console output) and lx-symbols
(useful for loading kernel module symbol information).

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Acked-by: Jerome Forissier <jerome@forissier.org>
diff --git a/qemu_v8.mk b/qemu_v8.mk
index 7c851d7..7a93fd2 100644
--- a/qemu_v8.mk
+++ b/qemu_v8.mk
@@ -154,6 +154,7 @@
 LINUX_COMMON_FLAGS += ARCH=arm64 Image
 
 linux: linux-common
+	$(MAKE) -C $(LINUX_PATH) $(LINUX_COMMON_FLAGS) scripts_gdb
 	mkdir -p $(BINARIES_PATH)
 	ln -sf $(LINUX_PATH)/arch/arm64/boot/Image $(BINARIES_PATH)