bluez5_utils: depends on BR2_TOOLCHAIN_HAS_SYNC_4

It uses __sync_fetch_and_add_4() and other 32-bit atomics, fixes:
http://autobuild.buildroot.net/results/498/4984850d872448c5702eac79b831891f77ad3cf0/



Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>