net: phy: nxp-c45-tja11xx: read ext trig ts on TJA1120

On TJA1120, the external trigger timestamp now has a VALID bit. This
changes the logic and we can't use the TJA1103 procedure.

For TJA1103, we can always read a valid timestamp from the registers,
compare the new timestamp with the old timestamp and, if they are not the
same, an event occurred. This logic cannot be applied for TJA1120 because
the timestamp is 0 if the VALID bit is not set.

Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Link: https://lore.kernel.org/r/20230731091619.77961-11-radu-nicolae.pirea@oss.nxp.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>