bnxt_en: Save ring error counters across reset

Currently, the ring counters are stored in the per ring datastructure.
During reset, all the rings are freed together with the associated
datastructures.  As a result, all the ring error counters will be reset
to zero.

Add logic to keep track of the total error counts of all the rings
and save them before reset (including ifdown).  The next patch will
display these total ring error counters under ethtool -S.

Link: https://lore.kernel.org/netdev/CACKFLimD-bKmJ1tGZOLYRjWzEwxkri-Mw7iFme1x2Dr0twdCeg@mail.gmail.com/
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20230817231911.165035-5-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>