package/mpd: add patch to fix linking with ogg

package/mpd: add patch to fix linking with ogg

Building mpds internal static xiph library needs to link with libogg.
Otherwise building mpd fails with:

```
/mips-linux-gnu/bin/ld: libxiph.a(libxiph_a-OggVisitor.o): undefined
reference to symbol 'ogg_stream_packetout'
```

Add a patch which adds OGG_LIBS to XIPH_LIBS so that the linker finds
the necessary ogg library.

Fixes:
http://autobuild.buildroot.net/results/9f0/9f062dc51daed5c5047faa8d79ecbd4e228f2572/
http://autobuild.buildroot.net/results/1cc/1cc097c5022bd3161dc03b0866cb04075c944a64/
http://autobuild.buildroot.net/results/2e3/2e3dbcdea34053675a0139c1911b6da1a6670e2c/
.. and more.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>