printk/console: Rename has_preferred_console to need_default_console

printk/console: Rename has_preferred_console to need_default_console

The logic around the variable @has_preferred_console made my head
spin many times. Part of the problem is the ambiguous name.

There is the variable @preferred_console. It points to the last
non-braille console in @console_cmdline array. This array contains
consoles preferred via the command line, device tree, or SPCR.

Then there is the variable @has_preferred_console. It is set to
"true" when @preferred_console is enabled or when a console with
tty binding gets enabled by default.

It might get reset back by the magic condition:

	if (!has_preferred_console || bcon || !console_drivers)
		has_preferred_console = preferred_console >= 0;

It is a puzzle. Dumb explanation is that it gets re-evaluated
when:

	+ it was not set before (see above when it gets set)
	+ there is still an early console enabled (bcon)
	+ there is no console enabled (!console_drivers)

This is still a puzzle.

It gets more clear when we see where the value is checked. The only
meaning of the variable is to decide whether we should try to enable
the new console by default.

Rename the variable according to the single situation where
the value is checked.

The rename requires an inverted logic. Otherwise, it is a simple
search & replace. It does not change the functionality.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Link: https://lore.kernel.org/r/20211122132649.12737-3-pmladek@suse.com