feat(hob): add HOB definitions to TFTF

Add necessary HOB structure definitions and HOB library to TFTF.

Signed-off-by: Kathleen Capella <kathleen.capella@arm.com>
Change-Id: I1a81cd99df52436a077a71030244ca642122497a
diff --git a/include/lib/libc/uuid.h b/include/lib/libc/uuid.h
index 3a1699b..8ba973d 100644
--- a/include/lib/libc/uuid.h
+++ b/include/lib/libc/uuid.h
@@ -51,6 +51,18 @@
 	uint8_t		node[_UUID_NODE_LEN];
 };
 
+struct efi_guid {
+	uint32_t time_low;
+	uint16_t time_mid;
+	uint16_t time_hi_and_version;
+	uint8_t clock_seq_and_node[8];
+};
+
+union uuid_helper_t {
+	struct uuid uuid_struct;
+	struct efi_guid efi_guid;
+};
+
 typedef struct uuid uuid_t;
 
 #endif /* _SYS_UUID_H_ */