emulators/wine: XAudio2 no longer depends on OpenAL

Since upstream commit 3e390b1aafff47df63376a8ca4293c515d74f4ba on
2019-02-20 XAudio2 uses FAudio (which already is an unconditional
dependency) and no longer depends on OpenAL, so adjust the packing
list accordingly. [1]

We did not detect this via regular testing due to false negatives
in Mk/Scripts/check-stagedir.sh in the presence of %%OPTION%%s in
pkg-plist. [2]

PR: 257651 [1], 220950 [2]
Submitted by: Alex S <iwtcex@gmail.com> [1]