scripts/xldd: stop at first match

Break the library search loop as soon as a match is found.
Previously, if a library was present in different places,
then the last occurence would be returned, when the first
one would have been used at runtime.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 reporter_name="Alexander BIGGA"

 reporter_url="http://sourceware.org/ml/crossgcc/2008-06/msg00031.html"

 reporter_comment=""