ip6r0_reserved is an array of octets; extract the value from it.

ip6r0_reserved is an array of octets; extract the value from it.

dp0->ip6r0_reserved evaluates to a pointer to the first element of the
array, which is always non-null, so it doesn't test whether the *value*
of the field is non-zero.  Call EXTRACT_32BITS() on it to check whether
the value is zero.