vt: fix regression warnings from KMS merge

Fix the following new sparse warnings in vt.c introduced by the commit
b45cfba4

 (vt,console,kdb: implement
atomic console enter/leave functions):

drivers/char/vt.c:197:5: warning: symbol 'saved_fg_console' was not declared. Should it be static?
drivers/char/vt.c:198:5: warning: symbol 'saved_last_console' was not declared. Should it be static?
drivers/char/vt.c:199:5: warning: symbol 'saved_want_console' was not declared. Should it be static?
drivers/char/vt.c:200:5: warning: symbol 'saved_vc_mode' was not declared. Should it be static?

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
CC: Andrew Morton <akpm@linux-foundation.org>