drm/i915: Use down ei for manual Baytrail RPS calculations

Use both up/down manual ei calcuations for symmetry and greater
flexibility for reclocking, instead of faking the down interrupt based
on a fixed integer number of up interrupts.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Deepak S<deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --cc drivers/gpu/drm/i915/i915_drv.h
Simple merge

diff --cc drivers/gpu/drm/i915/i915_irq.c
Simple merge

diff --cc drivers/gpu/drm/i915/i915_reg.h
Simple merge

diff --cc drivers/gpu/drm/i915/intel_pm.c
Simple merge