CVE-2017-5754

hwsync was added as a mnemonic for sync in binutils 2.25, prior
to that there is no support for hwsync. Replace uses of hwsync
with sync to maintain compatibility with older binutils.

Fixes: ee71154e ("UBUNTU: SAUCE: rfi-flush: Add barriers to the fallback L1D flushing")
Acked-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>