drm/i915: Fix incorrect definition of ADPA HSYNC and VSYNC bits

Disable bits for ADPA HSYNC and VSYNC where mixed up resulting in suspend
becoming standby and vice versa. Fixed by swapping their bit position.

Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>