alsa-lib: fix build on bfin

Bfin toolchains don't have versionsort (which alsa-lib needs), so fake it
using alphasort instead.

Fixes http://autobuild.buildroot.net/results/cf760651b2e238842813bf0882011b5fbb898c0d



Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>