PEM: Fix i2b_PvK to use EVP_Encrypt calls consistently

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/12574)

crypto/pem/pvkfmt.c

@@ -859,9 +859,9 @@ static int i2b_PVK(unsigned char **out, const EVP_PKEY *pk, int enclevel,
         if (!EVP_EncryptInit_ex(cctx, EVP_rc4(), NULL, keybuf, NULL))
             goto error;
         OPENSSL_cleanse(keybuf, 20);
-        if (!EVP_DecryptUpdate(cctx, p, &enctmplen, p, pklen - 8))
+        if (!EVP_EncryptUpdate(cctx, p, &enctmplen, p, pklen - 8))
             goto error;
-        if (!EVP_DecryptFinal_ex(cctx, p + enctmplen, &enctmplen))
+        if (!EVP_EncryptFinal_ex(cctx, p + enctmplen, &enctmplen))
             goto error;
     }