bnxt_en: Don't issue AP reset during ethtool's reset operation

Only older NIC controller's firmware uses the PROC AP reset type.
Firmware on 5731X/5741X and newer chips does not support this reset
type.  When bnxt_reset() issues a series of resets, this PROC AP
reset may actually fail on these newer chips because the firmware
is not ready to accept this unsupported command yet.  Avoid this
unnecessary error by skipping this reset type on chips that don't
support it.

Fixes: 7a13240e ("bnxt_en: fix ethtool_reset_flags ABI violations")
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>