mlxsw: spectrum_ptp: Rename mlxsw_sp_ptp_get_message_types()

Spectrum-1 and Spectrum-2 differ in their time stamping capabilities.
The former can be configured to time stamp only a subset of received PTP
events (e.g., only Sync), whereas the latter will time stamp all PTP
events or none.

In preparation for Spectrum-2 PTP support, rename the function that
parses the hardware time stamping configuration upon %SIOCSHWTSTAMP to
be Spectrum-1 specific.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>