net: ethernet: ti: am65-cpsw-qos: fix IET verify/response timeout

net: ethernet: ti: am65-cpsw-qos: fix IET verify/response timeout

The CPSW module uses the MAC_VERIFY_CNT bit field in the
CPSW_PN_IET_VERIFY_REG_k register to set the verify/response timeout
count. This register specifies the number of clock cycles to wait before
resending a verify packet if the verification fails.

The verify/response timeout count, as being set by the function
am65_cpsw_iet_set_verify_timeout_count() is hardcoded for 125MHz
clock frequency, which varies based on PHY mode and link speed.

The respective clock frequencies are as follows:
- RGMII mode:
  * 1000 Mbps: 125 MHz
  * 100 Mbps: 25 MHz
  * 10 Mbps: 2.5 MHz
- QSGMII/SGMII mode: 125 MHz (all speeds)

Fix this by adding logic to calculate the correct timeout counts
based on the actual PHY interface mode and link speed.

Fixes: 49a2eb9068246 ("net: ethernet: ti: am65-cpsw-qos: Add Frame Preemption MAC Merge support")
Signed-off-by: Aksh Garg <a-garg7@ti.com>
Link: https://patch.msgid.link/20251106092305.1437347-2-a-garg7@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>