Rename cli_classic.h to a more adequate cli_getop.h

The header only defines getop related stuff so it seems more intuitive
this way.

Change-Id: Iaceeabedc26e93147d8122376d88e730aad1e355
Signed-off-by: Antonio Vázquez Blanco <antoniovazquezblanco@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/85072
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

cli_getopt.c

@@ -25,12 +25,13 @@
  * SOFTWARE.
  */
 
+#include <cli_getopt.h>
+
 #include <unistd.h>
 #include <wchar.h>
 #include <string.h>
 #include <limits.h>
 #include <stdlib.h>
-#include "cli_classic.h"
 #include "flash.h"
 
 char *optarg;