staging: rtl8712: rtl871x_cmd.c: Remove unnecessary null check

Remove the check for whether the value of variable psecnetwork is NULL
as psecnetwork is a field of a field of a non-NULL pointer, and
therefore cannot be NULL itself.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>