Use internal FIPS 186-2 PRF if needed

Use internal FIPS 186-2 PRF if needed

Previously, EAP-SIM/AKA/AKA' did not work with number of crypto
libraries (GnuTLS, CryptoAPI, NSS) since the required FIPS 186-2 PRF
function was not implemented. This resulted in somewhat confusing error
messages since the placeholder functions were silently returning an
error. Fix this by using the internal implementation of FIP 186-2 PRF
(including internal SHA-1 implementation) with crypto libraries that do
not implement this in case EAP-SIM/AKA/AKA' is included in the build.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>