src/dvd_input.c: use dvdcss2.dll instead of dvdcss.dll on OS/2

libtool creates a versioned dll on OS/2 as well.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

src/dvd_input.c

@@ -303,7 +303,7 @@ int dvdinput_setup(void)
 #elif defined(WIN32)
   #define CSS_LIB "libdvdcss-2.dll"
 #elif defined(__OS2__)
-  #define CSS_LIB "dvdcss.dll"
+  #define CSS_LIB "dvdcss2.dll"
 #else
   #define CSS_LIB "libdvdcss.so.2"
 #endif