net: dsa: sja1105: round up PTP perout pin duration

net: dsa: sja1105: round up PTP perout pin duration

pin_duration is converted from the user-provided period to SJA1105
clock ticks and is later passed as the cycle_time argument to
future_base_time().

Very small period values may become zero after the conversion,
which can lead to a division by zero in future_base_time().

Round zero pin_duration up to 1 tick so that the smallest unsupported
periods use the minimum non-zero hardware duration instead of passing
zero to future_base_time().

Fixes: 747e5eb31d59 ("net: dsa: sja1105: configure the PTP_CLK pin as EXT_TS or PER_OUT")
Signed-off-by: Aleksandrova Alyona <aga@itb.spb.ru>
Link: https://patch.msgid.link/20260618110508.53094-1-aga@itb.spb.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>