staging: lustre: Deletion of unnecessary checks before three function calls

The following functions test whether their argument is NULL and then
return immediately.
* kfree
* ll_file_data_put
* ptlrpc_connection_put

Thus the test around such calls is not needed.

This issue was detected by using the Coccinelle software.

See also a previous update suggestion:
"remove unneeded null test before free" by Julia Lawall
https://lkml.org/lkml/2015/5/1/498
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg878600.html



Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>