apps/pkeyutl.c: Add OPENSSL_free() to avoid a memory leak

apps/pkeyutl.c: Add OPENSSL_free() to avoid a memory leak

If EVP_PKEY_CTX_ctrl_str() fails, the code jumps to 'end' label without freeing passwd, causing a memory leak.

Fixes: 9d1bf5f7de ("Add option to read pkeyopts interactively")
Signed-off-by: JiashengJiang <jiasheng@purdue.edu>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/27470)

(cherry picked from commit 0dc6ea55a13dbe27af234b5328527d0a31ae68eb)