x86/dsputil: fix VECTOR_CLIP_INT32 macro

The inline loop was incrementing and using the value of %%i
the wrong way.

Disassembly of ff_vector_clip_int32_sse2 before and after
this patch:

    movdqa (%rdx),%xmm0      |  movdqa (%rdx),%xmm0
    movdqa 0x10(%rdx),%xmm1  |  movdqa 0x10(%rdx),%xmm1
    movdqa 0x20(%rdx),%xmm2  |  movdqa 0x20(%rdx),%xmm2
    movdqa 0x30(%rdx),%xmm3  |  movdqa 0x30(%rdx),%xmm3
[...]                        |
    movdqa %xmm0,(%rcx)      |  movdqa %xmm0,(%rcx)
    movdqa %xmm1,0x10(%rcx)  |  movdqa %xmm1,0x10(%rcx)
    movdqa %xmm2,0x20(%rcx)  |  movdqa %xmm2,0x20(%rcx)
    movdqa %xmm3,0x30(%rcx)  |  movdqa %xmm3,0x30(%rcx)
    movdqa (%rdx),%xmm0      |  movdqa 0x40(%rdx),%xmm0
    movdqa 0x20(%rdx),%xmm1  |  movdqa 0x50(%rdx),%xmm1
    movdqa 0x40(%rdx),%xmm2  |  movdqa 0x60(%rdx),%xmm2
    movdqa 0x60(%rdx),%xmm3  |  movdqa 0x70(%rdx),%xmm3
[...]                        |
    movdqa %xmm0,(%rcx)      |  movdqa %xmm0,0x40(%rcx)
    movdqa %xmm1,0x20(%rcx)  |  movdqa %xmm1,0x50(%rcx)
    movdqa %xmm2,0x40(%rcx)  |  movdqa %xmm2,0x60(%rcx)
    movdqa %xmm3,0x60(%rcx)  |  movdqa %xmm3,0x70(%rcx)
    add    $0x80,%rdx        |  add    $0x80,%rdx
    add    $0x80,%rcx        |  add    $0x80,%rcx

Other versions were unaffected.

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
