[openssl/openssl] 457fd0: Modify the dkeyform type to support engine

[bangcheng]

  Branch: refs/heads/openssl-3.0
  Home:   https://github.com/openssl/openssl
  Commit: 457fd058da314cbbfe01443275a077cd930125f5
      https://github.com/openssl/openssl/commit/457fd058da314cbbfe01443275a077cd930125f5
  Author: wangcheng <bangwangnj at 163.com>
  Date:   2023-09-08 (Fri, 08 Sep 2023)

  Changed paths:
    M apps/s_server.c

  Log Message:
  -----------
  Modify the dkeyform type to support engine

The valtype value of dkeyform defined in the s_server_options structure is F, which leads to the judgment that the engine is not supported when processing parameters in the opt_next function.
This the valtype value of dkeyform should be changed to "f".

CLA: trivial

Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Paul Dale <pauli at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21982)

(cherry picked from commit b9a189ce87fde1de4bf691031624538262f005c5)