ARM: vfp: Move sending signals outside of vfp_lock()ed section.

VFP_bounce() is invoked from within vfp_support_entry() and may send a
signal. Sending a signal uses spinlock_t which becomes a sleeping lock
on PREEMPT_RT and must not be acquired within a preempt-disabled
section.

Move the vfp_raise_sigfpe() block outside of the vfp_lock() section.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>