Missing -lNE10 in opus.pc when building with NE10

[pfeatherstone]

The opus.pc file should have -lNE101 when building with NE10 FFT library.
Cheers.

[pfeatherstone]

There are a couple more issues when building with Ne10:

• When using autotools, there's no way to disable using Ne10 even when it's present
• When using CMake, there's no way to either enable or disable
• When Ne10 is enabled, the codec seems to be buggy and there is periodic software-induced clipping. I can provide spectrogram or recordings if necessary.

[xnorpx]

Regarding CMake the project felt pretty abandoned when I was writing the CMake scripts and I wasn't sure about how much performance improvement was for Armv8+ so I choose to not add it the time.