vt: vt_kern.h, remove the repeated declaration

Function 'vt_set_led_state' is declared twice, so remove the
repeated declaration.

Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Link: https://lore.kernel.org/r/1623062933-52943-1-git-send-email-zhangshaokun@hisilicon.com


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