efi_loader: Measure the loaded DTB

Measures the DTB passed to the EFI application upon new boolean config
switch CONFIG_EFI_TCG2_PROTOCOL_MEASURE_DTB. For platforms where the
content of the DTB passed to the OS can change across reboots, there is
not point measuring it hence the config switch to allow platform to not
embed this feature.

Co-developed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/include/efi_loader.h b/include/efi_loader.h
index c664d6c..1542b4b 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -531,6 +531,8 @@
 efi_status_t efi_tcg2_measure_efi_app_invocation(struct efi_loaded_image_obj *handle);
 /* Measure efi application exit */
 efi_status_t efi_tcg2_measure_efi_app_exit(void);
+/* Measure DTB */
+efi_status_t efi_tcg2_measure_dtb(void *dtb);
 /* Called by bootefi to initialize root node */
 efi_status_t efi_root_node_register(void);
 /* Called by bootefi to initialize runtime */