stm32cube: stm32h7: use transmit timestamp status flag.

Read timestamp only when status flag is set in Tx descriptor.
Fire transmit timestamp callbacks only when there is a valid
non-zero timestamp.

(cherry picked from commit d466dc8421ee0c6592bb5682aa93a671bc948107)

Original-Co-authored-by: Naeem Bacha <[email protected]>
Original-Signed-off-by: Chamira Perera <[email protected]>
GitOrigin-RevId: d466dc8421ee0c6592bb5682aa93a671bc948107
Change-Id: Ic216bb5d72be4570721d79b0d550fc4d790cb194
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/hal_stm32/+/4720447
Commit-Queue: Yuval Peress <[email protected]>
Tested-by: ChromeOS Prod (Robot) <[email protected]>
Reviewed-by: Yuval Peress <[email protected]>
Tested-by: Yuval Peress <[email protected]>
2 files changed