ksmbd: use kvzalloc instead of kvmalloc

[ Upstream commit 81a94b27 ]

Use kvzalloc instead of kvmalloc.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>