Revert "printk: Flag register_console() if console is set on command line"

This reverts commit b73c9cbe4f1fc02645228aa575998dd54067f8ef.

Let's roll back all of the serial core and printk console changes that
went into 6.10-rc1 as there still are problems with them that need to be
sorted out.

Link: https://lore.kernel.org/r/ZnpRozsdw6zbjqze@tlindgre-MOBL1
Reported-by: Petr Mladek <[e-mail]>
Reported-by: Tony Lindgren <[e-mail]>
Cc: Jiri Slaby <[e-mail]>
Cc: John Ogness <[e-mail]>
Cc: Sergey Senozhatsky <[e-mail]>
Cc: Andy Shevchenko <[e-mail]>
Cc: Ilpo Järvinen <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

kernel/printk/printk.c

···
 	if (console_opt_save(str, brl_options))
 		return 1;
 
-	/* Flag register_console() to not call try_enable_default_console() */
-	console_set_on_cmdline = 1;
-
 	/* Don't attempt to parse a DEVNAME:0.0 style console */
 	if (strchr(str, ':'))
 		return 1;
···
 	 * Note that a console with tty binding will have CON_CONSDEV
 	 * flag set and will be first in the list.
 	 */
-	if (preferred_console < 0 && !console_set_on_cmdline) {
+	if (preferred_console < 0) {
 		if (hlist_empty(&console_list) || !console_first()->device ||
 		    console_first()->flags & CON_BOOT) {
 			try_enable_default_console(newcon);