UBUNTU: SAUCE: i915_bpo: Disable preliminary hw support

It was mistakenly enabled, the option should be left disabled and
instead enable KBL/BXT via the driver once they have been properly
tested.
Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

debian.master/config/config.common.ubuntu

@@ -1963,7 +1963,7 @@ CONFIG_DRM_I2C_SIL164=m
 CONFIG_DRM_I810=m
 CONFIG_DRM_I915=m
 CONFIG_DRM_I915_BPO=m
-CONFIG_DRM_I915_BPO_PRELIMINARY_HW_SUPPORT=y
+CONFIG_DRM_I915_BPO_PRELIMINARY_HW_SUPPORT=n
 CONFIG_DRM_I915_BPO_USERPTR=y
 # CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT is not set
 CONFIG_DRM_IMX=m