uclibc: arc-2015.06 - add patches on top of release

This commit adds 2 patches on top of arc-2015.06 release:
 0001-nptl-remove-duplicate-vfork-in-libpthread.patch
 0002-ARCv2-update-memset-so-it-could-be-used-without-doub.patch

The first patch fixes multiple build issues when using static build like
http://autobuild.buildroot.net/results/b704016acfa38e7998739a2c70bcf6020c59bda8/



The second patch allows for building uClibc for ARCv2 based CPUs that
doesn't have 64-bit load/store capabilities.

Both patches should be a part of the next release/update of ARC GNU
tools so then they should be removed from Buildroot.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>