[efi] Attempt NII initialisation both with and without cable detection

[efi] Attempt NII initialisation both with and without cable detection

We currently use a heuristic to determine whether or not to request
cable detection in PXE_OPCODE_INITIALIZE, based on the need to work
around a known Emulex driver bug (see commit c0b61ba "[efi] Work
around bugs in Emulex NII driver") and the need to accommodate links
that are legitimately slow to come up (see commit 6324227 "[efi] Skip
cable detection at initialisation where possible").

This heuristic appears to fail with newer Emulex drivers.  Attempt to
support all known drivers (past and present) by first attempting
initialisation with cable detection, then falling back to attempting
initialisation without cable detection.

Reported-by: Kwang Woo Lee <kwleeyh@gmail.com>
Tested-by: Kwang Woo Lee <kwleeyh@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>