configs/rdn2cfg1: enables NUMACTL utilities

With NUMACTL configuration enabled in buildroot, NUMA test utilities
(NUMASTAT, NUMADEMO) will be available for performing various
NUMA specific test on all available NUMA nodes in kernel.

Signed-off-by: Sayanta Pattanayak <sayanta.pattanayak@arm.com>
Change-Id: I78b303d732b49c12d4a9a2be01f4d0b71c1f1d07