APPS: Replace 'OPT_ERR = -1, OPT_EOF = 0, OPT_HELP' by OPT_COMMON macro

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15111)

apps/genpkey.c

diff --git a/apps/genpkey.c b/apps/genpkey.c
index 746cd59..f10390e 100644
--- a/apps/genpkey.c
+++ b/apps/genpkey.c
@@ -20,7 +20,7 @@
 static int genpkey_cb(EVP_PKEY_CTX *ctx);
 
 typedef enum OPTION_choice {
-    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,
+    OPT_COMMON,
     OPT_ENGINE, OPT_OUTFORM, OPT_OUT, OPT_PASS, OPT_PARAMFILE,
     OPT_ALGORITHM, OPT_PKEYOPT, OPT_GENPARAM, OPT_TEXT, OPT_CIPHER,
     OPT_CONFIG,