staging: greybus: Change NULL comparison to Boolean Negation

Change NULL comparison to boolean negation. Issue found by Checkpatch.

Signed-off-by: Nishka Dasgupta <nishka.dasgupta@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nishka Dasgupta 2019-03-04 23:13:15 +05:30 • committed by Greg Kroah-Hartman
commit 35defd6dd1