vt: selection, remove redeclaration of poke_blanked_console

It is declared in vt_kern.h, so no need to declare it in selection.c
which includes the header.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-8-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/selection.c

@@ -35,8 +35,6 @@
 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
 #define isspace(c)	((c) == ' ')
 
-extern void poke_blanked_console(void);
-
 /* FIXME: all this needs locking */
 static struct vc_selection {
 	struct mutex lock;