package/mpd: fix build of GenParseName

Fix build of GenParseName which has been added in version 0.22:
https://github.com/MusicPlayerDaemon/MPD/commit/fa45a8adfa44f6bc815ae7428770112c15c76d73

Fixes:
 - http://autobuild.buildroot.org/results/871e1362c44e5b68a149e6a5dd3caf99ea0d904a



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>