tty: vt, fix bogus division in csi_J

In csi_J(3), the third parameter of scr_memsetw (vc_screenbuf_size) is
divided by 2 inappropriatelly. But scr_memsetw expects size, not
count, because it divides the size by 2 on its own before doing actual
memset-by-words.

So remove the bogus division.

Signed-off-by: Jiri Slaby <[e-mail]>
Cc: Petr Písař <[e-mail]>
Fixes: f8df13e0a9 (tty: Clean console safely)
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/vt/vt.c

···
 			break;
 		case 3: /* erase scroll-back buffer (and whole display) */
 			scr_memsetw(vc->vc_screenbuf, vc->vc_video_erase_char,
-				    vc->vc_screenbuf_size >> 1);
+				    vc->vc_screenbuf_size);
 			set_origin(vc);
 			if (con_is_visible(vc))
 				update_screen(vc);