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/sbshc.c b/drivers/acpi/sbshc.c
index a4e3767..001d914 100644
--- a/drivers/acpi/sbshc.c
+++ b/drivers/acpi/sbshc.c
@@ -282,7 +282,7 @@
 	hc->ec = acpi_driver_data(device->parent);
 	hc->offset = (val >> 8) & 0xff;
 	hc->query_bit = val & 0xff;
-	acpi_driver_data(device) = hc;
+	device->driver_data = hc;
 
 	acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
 	printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
@@ -303,7 +303,7 @@
 	hc = acpi_driver_data(device);
 	acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
 	kfree(hc);
-	acpi_driver_data(device) = NULL;
+	device->driver_data = NULL;
 	return 0;
 }