net/bnxt: add statistics

net/bnxt: add statistics

Add the bnxt_stats_get_op() and bnxt_stats_reset_op() dev_ops to
get and reset statistics. It also brings in the associated HWRM calls
to handle the requests appropriately.

We also have the bnxt_free_stats() function which will be used in the
follow on patches to free the memory allocated by the driver for
statistics.

New HWRM calls:
bnxt_hwrm_stat_clear:
	This command clears statistics of a context

Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Signed-off-by: Stephen Hurd <stephen.hurd@broadcom.com>
Reviewed-by: David Christensen <david.christensen@broadcom.com>