eal: fix log message print for regex

eal: fix log message print for regex

If user passes log-level eal parameter to enable log level based on regex
then in case of error message is being printed for pattern match instead of
regex. Following is the warning message thrown:

Compiling C object 'lib/76b5a35@@rte_eal@sta/librte_eal_common_eal_common_options.c.o'.
In function ‘eal_parse_log_level’,
   inlined from ‘eal_parse_common_option’ at ../lib/librte_eal/common/eal_common_options.c:1418:7:
../lib/librte_eal/common/eal_common_options.c:1053:4: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
 1053 |    fprintf(stderr, "cannot set log level %s,%d\n",
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1054 |     pattern, priority);
      |     ~~~~~~~~~~~~~~~~~~

Fixes: 7f0bb634a140 ("log: add ability to match log type with globbing")
Cc: stable@dpdk.org
Signed-off-by: Sunil Kumar Kori <skori@marvell.com>
Acked-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Jerin Jacob <jerinj@marvell.com>