staging: comedi: tests: example_test: Rename to 'comedi_example_test'

Rename the "example_test" module to "comedi_example_test" to make the
name more relevant to Comedi.

Cc: Spencer E. Olson <olsonse@umich.edu>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20210407181342.1117754-6-abbotti@mev.co.uk


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