bnxt_en: fix LRO/GRO_HW features in ndo_fix_features callback

LRO/GRO_HW should be disabled if there is an attached XDP program.
BNXT_FLAG_TPA is the current setting of the LRO/GRO_HW.  Using
BNXT_FLAG_TPA to disable LRO/GRO_HW will cause these features to be
permanently disabled once they are disabled.

Fixes: 1dc4c557 ("bnxt: adding bnxt_xdp_build_skb to build skb from multibuffer xdp_buff")
Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>