* config/arc/predicates.md (extend_operand): During/after reload,
        allow const_int_operand.
        * config/arc/arc.md (mulsidi3_700): Use extend_operand predicate.
        (umulsidi3_700): Likewise.  Change operand 2 constraint back to "cL".
        (mulsi3_highpart): Change operand 2 constraint alternatives 2 and 3
        to "i".
        (umulsi3_highpart_i): Likewise.