Provide fallback for keymaster implementations

Some implementations won't support ECDSA or DSA, so provide a fallback
for them by using the softkeymaster implementation. This will allow us
to universally support ECDSA and DSA on all platforms regardless of HAL
version.

(cherry picked from commit 17208e0de5a42722901d803118745cca25fd10c1)

Bug: 10600582
Change-Id: Ic02102cb2b7f66e2ad3469f4edd9d03c4ae3fdf4
8 files changed
tree: a891f22c48ea4a16258d04f0da0cfb56d84b72c4
  1. keystore/
  2. keystore-engine/
  3. softkeymaster/