package/kodi: needs BR2_TOOLCHAIN_HAS_SYNC_8

package/kodi: needs BR2_TOOLCHAIN_HAS_SYNC_8

Fixes a build error on arm detected by autobuilders:
http://autobuild.buildroot.net/results/439/43939f65e4516adddc4385c6e0a2193abcab0446/
http://autobuild.buildroot.net/results/322/322e3cd3b444106c9b624675c2265d4fdfefe458/
http://autobuild.buildroot.net/results/3c1/3c1a0e35325828c554f49ab9dbeb4b9b16f9b1e5/
http://autobuild.buildroot.net/results/222/222e8f3392a794b693ff0a9617453bdffbce8aef/
http://autobuild.buildroot.net/results/d91/d91efe30996ddbb4706885b48ff6d5d3fa974df8/

and this build error on BR2_x86_i486

xbmc/filesystem/filesystem.a(FileCache.o): In function `std::__atomic_base<long long>::store(long long, std::memory_order)':
/home/bernd/buildroot/br6_kodi_next/output/host/usr/i486-buildroot-linux-uclibc/include/c++/4.9.3/bits/atomic_base.h:478: undefined reference to `__atomic_store_8'
/home/bernd/buildroot/br6_kodi_next/output/host/usr/i486-buildroot-linux-uclibc/include/c++/4.9.3/bits/atomic_base.h:478: undefined reference to `__atomic_store_8'
xbmc/filesystem/filesystem.a(FileCache.o): In function `std::__atomic_base<long long>::load(std::memory_order) const':
/home/bernd/buildroot/br6_kodi_next/output/host/usr/i486-buildroot-linux-uclibc/include/c++/4.9.3/bits/atomic_base.h:500: undefined reference to `__atomic_load_8'

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>