misc: bcm-vk: only support ttyVK if CONFIG_TTY is set

Correct compile issue if CONFIG_TTY is not set by
only adding ttyVK devices if CONFIG_BCM_VK_TTY is set.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/r/20210203223826.21674-1-scott.branden@broadcom.com


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