ARM: 7873/1: vfp: clear vfp_current_hw_state for dying cpu

The CPU_DYING notifier is called by cpu stopper task which
does not own the context held in the VFP hardware. Calling
vfp_force_reload() has no effect.
Replace it with clearing vfp_current_hw_state.

Signed-off-by: Yuanyuan Zhong <zyy@motorola.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Lanchon <lanchon@gmail.com>
Force reload of the VFP context

Force reload of the VFP context, even if the up-to-date context
should already be in the hardware, to work around possible CPU
migration issues.

Change-Id: I1e130ca07c6cdd5c301466492154b9bea21df6a0
Signed-off-by: Lanchon <lanchon@gmail.com>