todo: remove fork protection todo comment, it isn't relevant to the FIPS provider

Fixes #12984
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/12997)

crypto/threads_pthread.c

@@ -195,8 +195,6 @@ int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock)
 }
 
 # ifndef FIPS_MODULE
-/* TODO(3.0): No fork protection in FIPS module yet! */
-
 #  ifdef OPENSSL_SYS_UNIX
 static pthread_once_t fork_once_control = PTHREAD_ONCE_INIT;