drm/i915: io unmap functions want __iomem

Don't cast away the __iomem from the io_mapping functions so that
sparse won't be so unhappy when we pass the pointer to the unmap
functions. Instead let's move the cast to where we actually use the
pointer.

Fixes the following sparse warnings:
i915_gem.c:1022:33: warning: incorrect type in argument 1 (different address spaces)
i915_gem.c:1022:33:    expected void [noderef] <asn:2>*vaddr
i915_gem.c:1022:33:    got void *[assigned] vaddr
i915_gem.c:1027:34: warning: incorrect type in argument 1 (different address spaces)
i915_gem.c:1027:34:    expected void [noderef] <asn:2>*vaddr
i915_gem.c:1027:34:    got void *[assigned] vaddr
i915_gem.c:1199:33: warning: incorrect type in argument 1 (different address spaces)
i915_gem.c:1199:33:    expected void [noderef] <asn:2>*vaddr
i915_gem.c:1199:33:    got void *[assigned] vaddr
i915_gem.c:1204:34: warning: incorrect type in argument 1 (different address spaces)
i915_gem.c:1204:34:    expected void [noderef] <asn:2>*vaddr
i915_gem.c:1204:34:    got void *[assigned] vaddr

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170901171252.31025-2-ville.syrjala@linux.intel.comReviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_gem.c

@@ -1013,17 +1013,20 @@ gtt_user_read(struct io_mapping *mapping,
 	      loff_t base, int offset,
 	      char __user *user_data, int length)
 {
-	void *vaddr;
+	void __iomem *vaddr;
 	unsigned long unwritten;
 
 	/* We can use the cpu mem copy function because this is X86. */
-	vaddr = (void __force *)io_mapping_map_atomic_wc(mapping, base);
-	unwritten = __copy_to_user_inatomic(user_data, vaddr + offset, length);
+	vaddr = io_mapping_map_atomic_wc(mapping, base);
+	unwritten = __copy_to_user_inatomic(user_data,
+					    (void __force *)vaddr + offset,
+					    length);
 	io_mapping_unmap_atomic(vaddr);
 	if (unwritten) {
-		vaddr = (void __force *)
-			io_mapping_map_wc(mapping, base, PAGE_SIZE);
-		unwritten = copy_to_user(user_data, vaddr + offset, length);
+		vaddr = io_mapping_map_wc(mapping, base, PAGE_SIZE);
+		unwritten = copy_to_user(user_data,
+					 (void __force *)vaddr + offset,
+					 length);
 		io_mapping_unmap(vaddr);
 	}
 	return unwritten;
@@ -1189,18 +1192,18 @@ ggtt_write(struct io_mapping *mapping,
 	   loff_t base, int offset,
 	   char __user *user_data, int length)
 {
-	void *vaddr;
+	void __iomem *vaddr;
 	unsigned long unwritten;
 
 	/* We can use the cpu mem copy function because this is X86. */
-	vaddr = (void __force *)io_mapping_map_atomic_wc(mapping, base);
-	unwritten = __copy_from_user_inatomic_nocache(vaddr + offset,
+	vaddr = io_mapping_map_atomic_wc(mapping, base);
+	unwritten = __copy_from_user_inatomic_nocache((void __force *)vaddr + offset,
 						      user_data, length);
 	io_mapping_unmap_atomic(vaddr);
 	if (unwritten) {
-		vaddr = (void __force *)
-			io_mapping_map_wc(mapping, base, PAGE_SIZE);
-		unwritten = copy_from_user(vaddr + offset, user_data, length);
+		vaddr = io_mapping_map_wc(mapping, base, PAGE_SIZE);
+		unwritten = copy_from_user((void __force *)vaddr + offset,
+					   user_data, length);
 		io_mapping_unmap(vaddr);
 	}