ulink: Move firmware install from pkglibdir to pkgdatadir

The precompiled OpenULINK firmware is just data to OpenOCD so I think it
belongs in $(prefix)/share/openocd rather than in $(prefix)/lib.

Change-Id: Id84c32cd0ddfb96861e903e8f23c16a81e1a0ca1
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/1487
Tested-by: jenkins
Reviewed-by: Martin Schmölzer <martin.schmoelzer@student.tuwien.ac.at>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>