eth: bnxt: switch to netif_close

All (error) paths that call dev_close are already holding instance lock,
so switch to netif_close to avoid the deadlock.

v2:
- add missing EXPORT_MODULE for netif_close

Fixes: 004b5008 ("eth: bnxt: remove most dependencies on RTNL")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250309215851.2003708-1-sdf@fomichev.me


Signed-off-by: Jakub Kicinski <kuba@kernel.org>