uclibc: add patch to fix fcntl64() on 64 bits targets

The patch is already in upstream uClibc, in the master branch, at
http://git.buildroot.net/uClibc/commit/?id=6f1daaaf2d94c1e6184add44eda38b0781b88cf0

.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>