ARM: 9228/1: vfp: kill vfp_flush/release_thread()

Those functions are removed since 2006 commit d6551e88
("[ARM] Add thread_notify infrastructure").

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>