feat(qemu): add dummy plat_mboot_measure_key() BL1 function

Adds a dummy implementation of the plat_mboot_measure_key() function in
BL1 for QEMU platform.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Change-Id: I5923aad962a5e34d657cf49c177e68ed2ea93291

plat/qemu/qemu/qemu_bl1_measured_boot.c

@@ -26,3 +26,9 @@ int plat_mboot_measure_image(unsigned int image_id, image_info_t *image_data)
 {
 	return 0;
 }
+
+int plat_mboot_measure_key(const void *pk_oid, const void *pk_ptr,
+			   size_t pk_len)
+{
+	return 0;
+}