[sw,crypto] Clear up some ECC naming confusion.
[sw,crypto] Clear up some ECC naming confusion.

Previously, "ECC" was used to refer to ECDSA and ECDH; with the addition
of Curve25519 algorithms, this became confusing. This pass rephrases
things to make the distinctions clearer and/or more specific.

Signed-off-by: Jade Philipoom <23b156e860ef6ab36b055884a79031aa7723874a@google.com>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan