MMX SIMD integer packed arithmetic instruction compile sucess quietly

[zanyoyi]

Using nasm (current master SHA commit: 6015afc) on following file (command: nasm -fwin32 -w+all test.asm -o test.obj -l test.lst)

dq_data:
        dq 0, 0

section .text code use32
        paddq           mm0, [dq_data]
        psubq           mm0, [dq_data]
        pmuludq         mm0, [dq_data]

        paddq           mm0, qword[dq_data]
        ; works as expected
        psubq           mm0, oword[dq_data]
        ; mismatch in operand size
        pmuludq         mm0, oword[dq_data]
        ; mismatch in operand size

does not show warning or error on incorrect mnemonic line 12 and 14.

[hpax]

Valid, but does not seem to be a regression.