printk/console: Remove unnecessary need_default_console manipulation

There is no need to clear @need_default_console when a console
preferred by the command line, device tree, or SPCR, gets enabled.

The code is called only when some non-braille console matched a console
in @console_cmdline array. It means that a non-braille console was added
in __add_preferred_console() and the variable preferred_console is set
to a number >= 0. As a result, @need_default_console is always set to
"false" in the magic condition:

	if (need_default_console || bcon || !console_drivers)
		need_default_console = preferred_console < 0;

This is one small step in removing the above magic condition
that is hard to follow.

The patch removes one superfluous assignment and should not change
the functionality.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20211122132649.12737-4-pmladek@suse.com