package/vlc: Fix SSE support with gcc5

package/vlc: Fix SSE support with gcc5

Compile fails

make[4]: Entering directory `/home/fli4l/br6_freeswitch/output/build/vlc-2.2.1/modules'
  CC       video_chroma/libi420_yuy2_sse2_plugin_la-i420_yuy2.lo
In file included from video_chroma/i420_yuy2.c:35:0:
video_chroma/i420_yuy2.c: In function 'I420_UYVY_Filter':
video_chroma/i420_yuy2.c:194:23: error: calling 'I420_UYVY.isra.2' with SSE caling convention without SSE/SSE2 enabled
 VIDEO_FILTER_WRAPPER( I420_UYVY )
                       ^
../include/vlc_filter.h:266:13: note: in definition of macro 'VIDEO_FILTER_WRAPPER'
             name( p_filter, p_pic, p_outpic );                          \

using this defconfig

BR2_x86_pentium2=y
BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
BR2_GCC_VERSION_5_1_X=y
BR2_TOOLCHAIN_BUILDROOT_CXX=y
BR2_PACKAGE_VLC=y

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>