net/bnxt: fix Tx timestamp init

net/bnxt: fix Tx timestamp init

Fix to read the sequence ID register to get Tx timestamp.
Reading the sequence ID register is necessary for the HW FIFO to
advance and thereby get the correct value of the timestamp on Tx side.
This patch fixes that.

Fixes: b11cceb83a34 ("net/bnxt: support timesync")
Cc: stable@dpdk.org
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Lance Richardson <lance.richardson@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>