tty/vt: consolemap: remove dflt reset from con_do_clear_unimap()

tty/vt: consolemap: remove dflt reset from con_do_clear_unimap()

con_do_clear_unimap() sets dflt to NULL and then calls
con_release_unimap() which does the very same as the first thing. So
remove the former as it is apparently superfluous.

Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220614090537.15557-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>