bluetooth: controller: remove select of ENTROPY_NRF_CRACEN_CTR_DRBG

ENTROPY_NRF_CRACEN_CTR_DRBG symbol is based on devicetree
node with compatible nordic,nrf-cracen-ctrdrbg. It does not
have to be selected explicitly.

Signed-off-by: Michał Stasiak <michal.stasiak@nordicsemi.no>