[nrf fromtree] scripts: imgtool: Fix verification with public ed25519 key file

Fixes an issue whereby ed25519 public keys were not supported for
verifying images which would wrongly give an error about the key
type not matching the TLV record

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
(cherry picked from commit a2ee0a7)
Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>

Author: nordicjm

scripts/imgtool/image.py

@@ -188,6 +188,7 @@ def tlv_sha_to_sha(tlv):
     keys.RSAPublic          : ['256'],
     # This two are set to 256 for compatibility, the right would be 512
     keys.Ed25519            : ['256', '512'],
+    keys.Ed25519Public      : ['256', '512'],
     keys.X25519             : ['256', '512']
 }