Fixed unchecked HMACs in Seal/Unseal. Implementing a small libcrypto
which should have HMAC/SHA/AES functions integrated as well as new
support for RSA. This is a requirement for Sboot support of signed
code updates.
Fixed bad patching, begin keyed/signature-based sboot.
Also added board config for BeagleBone (to mainline update).
Signature-based Sboot. 
Compiles but not tested, no implementation within U-Boot yet.
Support for signature-based verification.
Fixed a logic error with ENFORCE, added the option to report timer
information using CONFIG_SBOOT_TIMING. An RSA public key (currently
2048-bit) can be used to verify an RSA-SHA1-2048 signature using
CONFIG_SBOOT_KEYS. The public key can be stored in TPM NVRAM using
CONFIG_SBOOT_KEYSTORE_INDEX.
Conflicts:

	lib/sboot/sboot.c
	lib/sboot/sboot_keys.c