configure: Do not redundantly list enabled hwaccel libs

The enabled hwaccels are listed later anyway.
Signed-off-by: Mans Rullgard <mans@mansr.com>

configure

@@ -3805,9 +3805,6 @@ echo "network support           ${network-no}"
 echo "threading support         ${thread_type-no}"
 echo "safe bitstream reader     ${safe_bitstream_reader-no}"
 echo "SDL support               ${sdl-no}"
-echo "libdxva2 enabled          ${dxva2-no}"
-echo "libva enabled             ${vaapi-no}"
-echo "libvdpau enabled          ${vdpau-no}"
 echo "AVISynth enabled          ${avisynth-no}"
 echo "frei0r enabled            ${frei0r-no}"
 echo "gnutls enabled            ${gnutls-no}"