imgtool: Add sha512 to allowed configurations for ECDSA256P1

Added SHA512 to the list of supported algorithms for ECDSA256P1.

Signed-off-by: Lukasz Fundakowski <lukasz.fundakowski@nordicsemi.no>

Author: fundakol

scripts/imgtool/image.py

@@ -189,7 +189,7 @@ def tlv_sha_to_sha(tlv):
     keys.ECDSA384P1         : ['384'],
     keys.ECDSA384P1Public   : ['384'],
     keys.ECDSA256P1         : ['256'],
-    keys.ECDSA256P1Public   : ['256'],
+    keys.ECDSA256P1Public   : ['256', '512'],
     keys.RSA                : ['256'],
     keys.RSAPublic          : ['256'],
     # This two are set to 256 for compatibility, the right would be 512