staging: comedi: tests: Simplify conditional evaluation

Boolean comparison of the condition inside unittest function is
unnecessary and can be simplified by directly using the condition
outcome for evaluation. Issue reported by :
scripts/coccinelle/misc/boolinit.cocci

Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
Link: https://lore.kernel.org/r/20201019171426.GA72818@ubuntu204


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