multimedia/mswebrtc: unbreak build on i386

webrtc/webrtc/modules/audio_processing/aec/aec_core_sse2.c:46:31: error: always_inline function '_mm_loadu_ps' requires target feature 'mmx', but would be inlined into function 'FilterFarSSE2' that is compiled without support for 'mmx'

const __m128 xfBuf_re = _mm_loadu_ps(&aec->xfBuf[0][xPos + j]);
                        ^

webrtc/webrtc/modules/audio_processing/aec/aec_core_sse2.c:52:24: error: always_inline function '_mm_mul_ps' requires target feature 'mmx', but would be inlined into function 'FilterFarSSE2' that is compiled without support for 'mmx'

const __m128 a = _mm_mul_ps(xfBuf_re, wfBuf_re);
                 ^

webrtc/webrtc/modules/audio_processing/aec/aec_core_sse2.c:56:24: error: always_inline function '_mm_sub_ps' requires target feature 'mmx', but would be inlined into function 'FilterFarSSE2' that is compiled without support for 'mmx'

const __m128 e = _mm_sub_ps(a, b);
                 ^

webrtc/webrtc/modules/audio_processing/aec/aec_core_sse2.c:57:24: error: always_inline function '_mm_add_ps' requires target feature 'mmx', but would be inlined into function 'FilterFarSSE2' that is compiled without support for 'mmx'

const __m128 f = _mm_add_ps(c, d);
                 ^

webrtc/webrtc/modules/audio_processing/aec/aec_core_sse2.c:60:7: error: always_inline function '_mm_storeu_ps' requires target feature 'mmx', but would be inlined into function 'FilterFarSSE2' that is compiled without support for 'mmx'

_mm_storeu_ps(&yf[0][j], g);
^

webrtc/webrtc/modules/audio_processing/aec/aec_core_sse2.c:78:26: error: always_inline function '_mm_set1_ps' requires target feature 'mmx', but would be inlined into function 'ScaleErrorSignalSSE2' that is compiled without support for 'mmx'

const __m128 k1e_10f = _mm_set1_ps(1e-10f);
                       ^

fatal error: too many errors emitted, stopping now [-ferror-limit=]

Reported by: pkg-fallout