kernfs: mount: Remove unnecessary ‘NULL’ values from knparent

knparent is assigned first, so it does not need to initialize the
assignment.

Signed-off-by: Li zeming <zeming@nfschina.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240415102009.9926-1-zeming@nfschina.com


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