[openssl/openssl] 9ab57f: Coverity 1515953: negative loop bound

[Pauli]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 9ab57f29c78d8d69b6ba9c579521594d7170ca44
      https://github.com/openssl/openssl/commit/9ab57f29c78d8d69b6ba9c579521594d7170ca44
  Author: Pauli <pauli at openssl.org>
  Date:   2022-10-14 (Fri, 14 Oct 2022)

  Changed paths:
    M crypto/encode_decode/encoder_pkey.c

  Log Message:
  -----------
  Coverity 1515953: negative loop bound

Reviewed-by: Hugo Landau <hlandau at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Shane Lontis <shane.lontis at oracle.com>
(Merged from https://github.com/openssl/openssl/pull/19413)