vc: simplify condition in vc_con_write_normal

Convert (!(A && !B) || C) into (!A || B || C) to improve readability.

No functional changes, as was just proven by objdump.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200615074910.19267-20-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>