configure: check for ID3D11VideoContext

Should fix compilation with mingw-w64 trunk, where ID3D11VideoDecoder is available
but ID3D11VideoContext still isn't.
Signed-off-by: James Almer <jamrial@gmail.com>

configure

@@ -2381,7 +2381,7 @@ zmbv_encoder_select="zlib"
 
 # hardware accelerators
 crystalhd_deps="libcrystalhd_libcrystalhd_if_h"
-d3d11va_deps="d3d11_h dxva_h ID3D11VideoDecoder"
+d3d11va_deps="d3d11_h dxva_h ID3D11VideoDecoder ID3D11VideoContext"
 dxva2_deps="dxva2api_h DXVA2_ConfigPictureDecode"
 vaapi_deps="va_va_h"
 vda_deps="VideoDecodeAcceleration_VDADecoder_h pthreads CoreServices_CoreServices_h"
@@ -5154,6 +5154,7 @@ check_struct "sys/time.h sys/resource.h" "struct rusage" ru_maxrss
 
 check_type "windows.h dxva.h" "DXVA_PicParams_HEVC" -DWINAPI_FAMILY=WINAPI_FAMILY_DESKTOP_APP -D_CRT_BUILD_DESKTOP_APP=0
 check_type "windows.h d3d11.h" "ID3D11VideoDecoder"
+check_type "windows.h d3d11.h" "ID3D11VideoContext"
 check_type "d3d9.h dxva2api.h" DXVA2_ConfigPictureDecode -D_WIN32_WINNT=0x0602
 
 check_type "va/va.h" "VAPictureParameterBufferHEVC"