xf86_OSlib.h: Don't need to include Solaris keyboard headers here

Left over from the builtin keyboard driver removed from the Xorg server in 2006 (commit 3eeb62e8).

Requires xorg/driver/xf86-input-keyboard@40ef7d9e to build the current keyboard driver with this change.

Signed-off-by: Alan Coopersmith alan.coopersmith@oracle.com