f2fs: fix repair

calling fsck.f2fs without any argument will actually just check without any action.
with ‘-a’ an automatic repair is attempted, which is also the expected behavior when using this option.

Change-Id: I63df3dd6d28ad6a9e590ea8011585693985a035c
diff --git a/partition.cpp b/partition.cpp
index b0cd234..ab87b15 100755
--- a/partition.cpp
+++ b/partition.cpp
@@ -1980,7 +1980,7 @@
 			return false;
 		gui_msg(Msg("repairing_using=Repairing {1} using {2}...")(Display_Name)("fsck.f2fs"));
 		Find_Actual_Block_Device();
-		command = "/system/bin/fsck.f2fs " + Actual_Block_Device;
+		command = "/system/bin/fsck.f2fs -a " + Actual_Block_Device;
 		LOGINFO("Repair command: %s\n", command.c_str());
 		if (TWFunc::Exec_Cmd(command) == 0) {
 			gui_msg("done=Done.");