x509_print_ex:Use correct constant for nmflag comparison

x509_print_ex:Use correct constant for nmflag comparison

The X509_FLAG_COMPAT constant is defined as a value of the
X509_print_ex() cflags argument, and so it should not be used
to compare against values for use with X509_NAME_print flags.
Use XN_FLAG_COMPAT, which has the same value, instead.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Todd Short <todd.short@me.com>
(Merged from https://github.com/openssl/openssl/pull/19963)

(cherry picked from commit da2dd3b51ddd69aae0fd840c0d23afa954c24ded)