ACPI: catch calls of acpi_driver_data on pointer of wrong type

Catch attempts to use of acpi_driver_data on pointers of wrong type.

akpm: rewritten to use proper C typechecking and remove the
"function"-used-as-lvalue thing.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 13593f9..5741d99 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -788,7 +788,7 @@
 
 	if (!first_ec)
 		first_ec = ec;
-	acpi_driver_data(device) = ec;
+	device->driver_data = ec;
 	acpi_ec_add_fs(device);
 	pr_info(PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
 			  ec->gpe, ec->command_addr, ec->data_addr);
@@ -813,7 +813,7 @@
 	}
 	mutex_unlock(&ec->lock);
 	acpi_ec_remove_fs(device);
-	acpi_driver_data(device) = NULL;
+	device->driver_data = NULL;
 	if (ec == first_ec)
 		first_ec = NULL;
 	kfree(ec);