Staging: wlan-ng: Do not print message if kzalloc() failed.

Do not print message if kzalloc() failed.
kzalloc() has its own messages. So no need to add extra one.

Signed-off-by: Sandhya Bankar <bankarsandhya512@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>