bnxt_en: Convert to use netif_level() helpers.
Use the various netif_level() helpers to simplify the C code. This was suggested by Joe Perches. Cc: Joe Perches <joe@perches.com> Signed-off-by: Michael Chan <michael.chan@broadcom.com> Link: https://lore.kernel.org/r/1611642024-3166-1-git-send-email-michael.chan@broadcom.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>