staging: wfx: drop useless struct hif_map_link_flags

Struct hif_map_link_flags has no reason to exist. Drop it and simplify
access to struct hif_req_map_link.

Also rename the field 'map_direction' in 'unmap'. It is more
meaningful and allows to drop enum hif_sta_map_direction.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200907101521.66082-15-Jerome.Pouiller@silabs.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>