ARM: vfp: Always save VFP state in vfp_pm_suspend

ARM: vfp: Always save VFP state in vfp_pm_suspend

vfp_pm_suspend should save the VFP state in suspend after
any lazy context switch.  If it only saves when the VFP is enabled,
the state can get lost when, on a UP system:
  Thread 1 uses the VFP
  Context switch occurs to thread 2, VFP is disabled but the
     VFP context is not saved
  Thread 2 initiates suspend
  vfp_pm_suspend is called with the VFP disabled, and the unsaved
     VFP context of Thread 1 in the registers

Modify vfp_pm_suspend to save the VFP context whenever
vfp_current_hw_state is not NULL.

Change-Id: I91f29722d256a3afc1cc04df8b227541434ccffb
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Barry Song <bs14@csr.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Colin Cross <ccross@android.com>