enable clone system call for x86

Add __bionic_clone function for x86, which will be
used for clone system call.

Change-Id: I889dc9bf4b7ebb4358476e17e6f3233e26491f4d
Signed-off-by: Jin Wei <wei.a.jin@intel.com>
Signed-off-by: Xiaokang Qin <xiaokang.qin@intel.com>
Signed-off-by: Beare, Bruce J <bruce.j.beare@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 51414