net: stmmac: add aux timestamps fifo clearance wait

net: stmmac: add aux timestamps fifo clearance wait

commit ae9dcb91c6069e20b3b9505d79cbc89fd6e086f5 upstream.

Add timeout polling wait for auxiliary timestamps snapshot FIFO clear bit
(ATSFC) to clear. This is to ensure no residue fifo value is being read
erroneously.

Fixes: f4da56529da6 ("net: stmmac: Add support for external trigger timestamping")
Cc: <stable@vger.kernel.org> # 5.10.x
Signed-off-by: Noor Azura Ahmad Tarmizi <noor.azura.ahmad.tarmizi@intel.com>
Link: https://lore.kernel.org/r/20230111050200.2130-1-noor.azura.ahmad.tarmizi@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>