gpt: add optional parameter type in gpt command

code under flag CONFIG_PARTITION_TYPE_GUID
add parameter "type" to select partition type guid

example of use with gpt command :

  partitions = uuid_disk=${uuid_gpt_disk}; \
      name=boot,size=0x6bc00,uuid=${uuid_gpt_boot}; \
      name=root,size=0x7538ba00,uuid=${uuid_gpt_root}, \
         type=0fc63daf-8483-4772-8e79-3d69d8477de4;

  gpt write mmc 0 $partitions

Signed-off-by: Patrick Delaunay <patrick.delaunay73@gmail.com>
diff --git a/common/cmd_gpt.c b/common/cmd_gpt.c
index c56fe15..e3c0297 100644
--- a/common/cmd_gpt.c
+++ b/common/cmd_gpt.c
@@ -218,6 +218,23 @@
 			strcpy((char *)parts[i].uuid, p);
 			free(val);
 		}
+#ifdef CONFIG_PARTITION_TYPE_GUID
+		/* guid */
+		val = extract_val(tok, "type");
+		if (val) {
+			/* 'type' is optional */
+			if (extract_env(val, &p))
+				p = val;
+			if (strlen(p) >= sizeof(parts[i].type_guid)) {
+				printf("Wrong type guid format for partition %d\n",
+				       i);
+				errno = -4;
+				goto err;
+			}
+			strcpy((char *)parts[i].type_guid, p);
+			free(val);
+		}
+#endif
 		/* name */
 		val = extract_val(tok, "name");
 		if (!val) { /* name is mandatory */