SUNRPC: Remove per-enctype Kconfig options

SUNRPC: Remove per-enctype Kconfig options

The RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA1,
RPCSEC_GSS_KRB5_ENCTYPES_CAMELLIA, and
RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA2 Kconfig options
originally gated both algorithm availability and the
advertised enctype list. Now that per-message crypto
operations are routed through crypto/krb5, these options
control only which enctype numbers appear in the gssd
upcall string; the underlying algorithms are always
present.

Remove the per-enctype Kconfig options and replace the
ifdef-gated enctype table with a candidate list looked
up in the crypto/krb5 enctype table at module init
time. Each enctype is included in the advertised list
only if crypto_krb5_find_enctype() finds it in the
library's enctype table. When a new enctype is added
to crypto/krb5, adding its constant to the candidate
array is sufficient to begin advertising it.

Assisted-by: Claude:claude-opus-4-6
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Anna Schumaker <anna.schumaker@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>