staging: comedi: mite: Replace function mite_request_channel_in_range()

Remove function mite_request_channel_in_range as all it does is call
__mite_request_channel.
Rename __mite_request_channel to mite_request_channel_in_range and
change its type from static to non-static to maintain compatibility with
call sites.
Change only remaining call site of __mite_request_channel to call
mite_request_channel_in_range_instead.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20190701070025.3838-3-nishkadg.linux@gmail.com


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