drm/i915: Remove i915.enable_ppgtt override

Now that we are confident in providing full-ppgtt where supported,
remove the ability to override the context isolation.

v2: Remove faked aliasing-ppgtt for testing as it no longer is accepted.
v3: s/USES/HAS/ to match usage and reject attempts to load the module on
old GVT-g setups that do not provide support for full-ppgtt.
v4: Insulate ABI ppGTT values from our internal enum (later plans
involve moving ppGTT depth out of the enum, thus potentially breaking
ABI unless we document the current values).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Zhi Wang <zhi.a.wang@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180926201222.5643-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
index 6eecd64..af70026 100644
--- a/drivers/gpu/drm/i915/intel_device_info.h
+++ b/drivers/gpu/drm/i915/intel_device_info.h
@@ -25,6 +25,8 @@
 #ifndef _INTEL_DEVICE_INFO_H_
 #define _INTEL_DEVICE_INFO_H_
 
+#include <uapi/drm/i915_drm.h>
+
 #include "intel_display.h"
 
 struct drm_printer;
@@ -74,21 +76,25 @@ enum intel_platform {
 	INTEL_MAX_PLATFORMS
 };
 
+enum intel_ppgtt {
+	INTEL_PPGTT_NONE = I915_GEM_PPGTT_NONE,
+	INTEL_PPGTT_ALIASING = I915_GEM_PPGTT_ALIASING,
+	INTEL_PPGTT_FULL = I915_GEM_PPGTT_FULL,
+	INTEL_PPGTT_FULL_4LVL,
+};
+
 #define DEV_INFO_FOR_EACH_FLAG(func) \
 	func(is_mobile); \
 	func(is_lp); \
 	func(is_alpha_support); \
 	/* Keep has_* in alphabetical order */ \
 	func(has_64bit_reloc); \
-	func(has_aliasing_ppgtt); \
 	func(has_csr); \
 	func(has_ddi); \
 	func(has_dp_mst); \
 	func(has_reset_engine); \
 	func(has_fbc); \
 	func(has_fpga_dbg); \
-	func(has_full_ppgtt); \
-	func(has_full_48bit_ppgtt); \
 	func(has_gmch_display); \
 	func(has_guc); \
 	func(has_guc_ct); \
@@ -154,6 +160,7 @@ struct intel_device_info {
 	enum intel_platform platform;
 	u32 platform_mask;
 
+	enum intel_ppgtt ppgtt;
 	unsigned int page_sizes; /* page sizes supported by the HW */
 
 	u32 display_mmio_offset;