MIPS: trap is not needed if divisor is not zero

[wzssyqa]

int m(int a) {return a/1234;}

will be built to

        li      $2,1234                 # 0x4d2
        teq     $2,$0,7
        div     $0,$4,$2
        jr      $31
        mfhi    $2

Here the teq is not needed.

[llvmbot]

@llvm/issue-subscribers-backend-mips

Author: YunQiang Su (wzssyqa)

``` int m(int a) {return a/1234;} ```

will be built to

        li      $2,1234                 # 0x4d2
        teq     $2,$0,7
        div     $0,$4,$2
        jr      $31
        mfhi    $2

Here the teq is not needed.

[brad0]

cc @yingopq