sfc: improve PTP error reporting

sfc: improve PTP error reporting

BugLink: https://bugs.launchpad.net/bugs/1836635
Log a message if PTP probing fails; if we then, unexpectedly, get PTP
 events, only log a message for the first one on each device.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit acaef3c15612d7b0f5a4835f57e87a290e054839)
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>