efi_loader: error handling in tcg2_hash_pe_image()

If the hard coded array hash_algo_list[] contains an entry for an
unsupported algorithm, we should not leak resources new_efi and regs.

We should still extend the log with the digests for the supported
algorithms and not write any message.

The same holds true of tcg2_create_digest(): just continue in case
hash_algo_list[] contains an unsupported entry.

Fixes: 163a0d7e ("efi_loader: add PE/COFF image measurement")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>