[build] 'make reset' target will continue recursive operations if any…

… fail (#4675)

This change allows the recursive `git clean` and `git reset` commands to continue even if they encounter an error in one of the submodules. Previously, if an error was encountered, the operation would terminate with a message similar to the following:

Stopping at 'src/sonic-mgmt-framework'; script returned non-zero status.

Makefile.work

@@ -252,8 +252,8 @@ reset :
 	        fi
 	        git clean -xfdf;
 	        git reset --hard;
-	        git submodule foreach --recursive git clean -xfdf;
-	        git submodule foreach --recursive git reset --hard;
+	        git submodule foreach --recursive 'git clean -xfdf || true';
+	        git submodule foreach --recursive 'git reset --hard || true';
 	        git submodule update --init --recursive;
 	        echo "Reset complete!";
 	    else