bluetooth: host/crypto: fix the psa crypto init for host

psa_crypto_init was bounded to CONFIG_BT_HOST_CRYPTO_PRNG and
used to be called under prng_init. Updating the ifdef condition
and appropriating the function name for crypto init.

Also it is better to make sure psa_crypto_init called by host.

Signed-off-by: alperen sener <alperen.sener@nordicsemi.no>