postgresql: disable spinlock support for arcle/arcbe

Fixes:
  http://autobuild.buildroot.net/results/9b2/9b20513253fa68a3eb5588464a206092bb45e82d
  http://autobuild.buildroot.net/results/8ea/8ea59872bd68d302a11681426a47c70d9aa1475f
  http://autobuild.buildroot.net/results/4a1/4a1cf5721af631e15e076a5bcdd8676839c2a98d
  http://autobuild.buildroot.net/results/050/050a799f2e9e864e02cf75b2a5697ece215ab0a2



Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>