decoder: keep the lock around DecoderWaitDate() and aout_DecPlay()
decoder: keep the lock around DecoderWaitDate() and aout_DecPlay()

DecoderWaitDate() needs to return with the lock held to fix #5825.
Anyway, there was not much point in releasing the lock after
DecoderWaitUnblock() and acquire it again without sleeping.

aout_DecPlay() needs the lock, since the aout is not reentrant.

shyamalschandra/vlc,vlc-mirror/vlc,xkfz007/vlc,shyamalschandra/vlc,shyamalschandra/vlc,shyamalschandra/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,krichter722/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,xkfz007/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.1,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,xkfz007/vlc,krichter722/vlc,vlc-mirror/vlc-2.1,vlc-mirror/vlc-2.1,vlc-mirror/vlc,vlc-mirror/vlc,vlc-mirror/vlc-2.1,xkfz007/vlc,vlc-mirror/vlc,krichter722/vlc,xkfz007/vlc,krichter722/vlc,jomanmuk/vlc-2.1,jomanmuk/vlc-2.1,shyamalschandra/vlc,jomanmuk/vlc-2.1,krichter722/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,vlc-mirror/vlc-2.1,krichter722/vlc,jomanmuk/vlc-2.1,shyamalschandra/vlc,xkfz007/vlc,shyamalschandra/vlc,vlc-mirror/vlc,vlc-mirror/vlc-2.1,krichter722/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2