drm/i915: num_pd_pages/num_pd_entries isn't useful

These values are never quite useful for dynamic allocations of the page
tables. Getting rid of them will help prevent later confusion.

v2: Updated to use unmap_and_free_pd functions.
v3: Updated gen8_ppgtt_free after teardown logic was removed.
v4: Rebase after s/page_tables/page_table/.
v5: Keep allocating all page directories in GEN8+ systems with less
than 4GB of memory. Updated gen6_for_all_pdes.
v6: Prevent (harmless) out of range access in gen6_for_all_pdes.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Michel Thierry <michel.thierry@intel.com> (v2+)
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index acf8ed7..c3d5d40 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -314,8 +314,6 @@
 	struct kref ref;
 	struct drm_mm_node node;
 	unsigned long pd_dirty_rings;
-	unsigned num_pd_entries;
-	unsigned num_pd_pages; /* gen8+ */
 	union {
 		struct i915_page_directory_pointer pdp;
 		struct i915_page_directory pd;
@@ -350,6 +348,11 @@
 	     temp = min_t(unsigned, temp, length), \
 	     start += temp, length -= temp)
 
+#define gen6_for_all_pdes(pt, ppgtt, iter)  \
+	for (iter = 0;		\
+	     pt = ppgtt->pd.page_table[iter], iter < I915_PDES;	\
+	     iter++)
+
 static inline uint32_t i915_pte_index(uint64_t address, uint32_t pde_shift)
 {
 	const uint32_t mask = NUM_PTE(pde_shift) - 1;