SST: Fix build issue when SST_ENCRYPTION is OFF

Fixes some uses of old error types in sst_read_object that caused a
build failure when SST_ENCRYPTION was set to off.

Change-Id: Ic67c68654916da96fcdb40aa9510ed6003d4a81c
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
1 file changed