FindSndFile: Link mpg123 in static builds

[fwcd]

Based on #13085

This fixes another linker error in static builds that link libsndfile (before vs. after):

/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux-release/lib/libsndfile.a(mpeg_decode.c.o): in function `mpeg_dec_byterate':
mpeg_decode.c:(.text+0x36): undefined reference to `mpg123_info2'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux-release/lib/libsndfile.a(mpeg_decode.c.o): in function `mpeg_dec_seek':
mpeg_decode.c:(.text+0xa6): undefined reference to `mpg123_seek'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux-release/lib/libsndfile.a(mpeg_decode.c.o): in function `mpeg_dec_read_f':
mpeg_decode.c:(.text+0x112): undefined reference to `mpg123_read'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux-release/lib/libsndfile.a(mpeg_decode.c.o): in function `mpeg_dec_close':
mpeg_decode.c:(.text+0x273): undefined reference to `mpg123_close'
/usr/bin/ld: mpeg_decode.c:(.text+0x27c): undefined reference to `mpg123_delete'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux-release/lib/libsndfile.a(mpeg_decode.c.o): in function `mpeg_dec_read_s':
mpeg_decode.c:(.text+0x3c0): undefined reference to `mpg123_read'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux-release/lib/libsndfile.a(mpeg_decode.c.o): in function `mpeg_dec_read_i':
mpeg_decode.c:(.text+0x500): undefined reference to `mpg123_read'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux-release/lib/libsndfile.a(mpeg_decode.c.o): in function `mpeg_dec_read_d':
mpeg_decode.c:(.text+0x64a): undefined reference to `mpg123_read'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux-release/lib/libsndfile.a(mpeg_decode.c.o): in function `mpeg_decoder_init':
mpeg_decode.c:(.text+0x7d9): undefined reference to `mpg123_init'

[daschuer]

the mpg123 dependency has been added from sndlfile 1.2. So we need to put here a version guard.

By the way, it could be interesting to check the offset compared to libmad regarding mp3 decoding.

[fwcd]

The port's blame suggests that 1.1.0 was the first version to introduce this dependency, so that's what I used for the version check.

[daschuer]

LGTM, thank you