Fix SPU alpha channel palette values
Fix SPU alpha channel palette values

To convert from 4-bits to 8-bits channel, one should multiply by 17.

Acked-by: Antoine Cellerier <0253eed6e0d7831ef874b21a7f2d333fd2f7b461@videolan.org>

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