libmkv: enable x86 and x86_64
libmkv: enable x86 and x86_64

* some clean up

haikuports/haikuports,Begasus/haikuports,miqlas/haikuports,nielx/haikuports,nielx/haikuports,moochris/haikuports,haikuports/haikuports,Begasus/haikuports,miqlas/haikuports,koletzky/haikuports,koletzky/haikuports,Begasus/haikuports,Begasus/haikuports,miqlas/haikuports,nielx/haikuports,moochris/haikuports,haikuports/haikuports,koletzky/haikuports,Begasus/haikuports,haikuports/haikuports,haikuports/haikuports,moochris/haikuports