staging: vt6656: Remove unused rf_type in rf.c; unused variables

Remove rf_type that supports 5GHz band.

Follow up of previous patch. Remove unused tables.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/25e03c91ad7da064b69f3ac7eec265af70829aec.1646935331.git.philipp.g.hortmann@gmail.com


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