cryptfs: Remove Speck support

Remove the Speck encryption support. It was eventually
decided not to allow Speck in Android P, so this code
is no longer needed and wasn't used outside of testing.

Note we don't just "git revert" the original commit
(38723f23ff) because we want
to retain the infrastructure for allowing new types of
crypto algorithms in the future.

Bug: 112009351
Test: Attempted to setup a device with ro.crypto.fde_algorithm set to Speck, and Speck was rejected and the system defaulted to AES.
Change-Id: I69a8b4e8632f8d30b5b54783cb986ab42d4397d9

cryptfs.cpp

@@ -322,10 +322,6 @@ constexpr CryptoType default_crypto_type = CryptoType()
 
 constexpr CryptoType supported_crypto_types[] = {
     default_crypto_type,
-    CryptoType()
-        .set_property_name("Speck128/128-XTS")
-        .set_crypto_name("speck128-xts-plain64")
-        .set_keysize(32),
     // Add new CryptoTypes here.  Order is not important.
 };