[openssl/openssl] ffef6d: Correct documentation for PKCS5_PBKDF2_HMAC

[heygauri]

  Branch: refs/heads/openssl-3.1
  Home:   https://github.com/openssl/openssl
  Commit: ffef6d8f4da20a448421566f63e3283e0986c75b
      https://github.com/openssl/openssl/commit/ffef6d8f4da20a448421566f63e3283e0986c75b
  Author: Sumitra Sharma <sumitraartsy at gmail.com>
  Date:   2023-10-04 (Wed, 04 Oct 2023)

  Changed paths:
    M doc/man3/PKCS5_PBKDF2_HMAC.pod

  Log Message:
  -----------
  Correct documentation for PKCS5_PBKDF2_HMAC

In OpenSSL 3.x, the documentation for PKCS5_PBKDF2_HMAC incorrectly states
that an iter value less than 1 is treated as a single iteration. Upon further
investigation in providers/implementations/kdfs/pbkdf2.c, it appears that
invalid iter values will result in failure and raise the
PROV_R_INVALID_ITERATION_COUNT error. This commit corrects the documentation
to accurately reflect the behavior in OpenSSL 3.x.

Closes openssl#22168

Signed-off-by: Sumitra Sharma <sumitraartsy at gmail.com>

Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22252)

(cherry picked from commit 82496b8663f20ff12f02adbe46a060a94b0cbfc5)