avcodec/h264: Fix HWACCEL_MAX for D3D11

Found-by: philipl
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/h264_slice.c

@@ -863,6 +863,7 @@ static void init_scan_tables(H264Context *h)
 static enum AVPixelFormat get_pixel_format(H264Context *h, int force_callback)
 {
 #define HWACCEL_MAX (CONFIG_H264_DXVA2_HWACCEL + \
+                     CONFIG_H264_D3D11VA_HWACCEL + \
                      CONFIG_H264_VAAPI_HWACCEL + \
                      (CONFIG_H264_VDA_HWACCEL * 2) + \
                      CONFIG_H264_VDPAU_HWACCEL)