[AArch64]Fix the problem that can't select mul of v1i64/v2i64 types.
E.g. Can't select such IR:
     %tmp = mul <2 x i64> %a, %b


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198188 91177308-0d34-0410-b5e6-96231b3b80d8