ACPI: thinkpad-acpi: use bitfields to hold subdriver flags

Save some memory by using bitfields to hold boolean flags for the
subdrivers.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/misc/thinkpad_acpi.h

@@ -157,12 +157,13 @@ struct ibm_struct {
 
 	struct list_head all_drivers;
 
-	int driver_registered;
-	int proc_created;
-	int init_called;
-	int notify_installed;
-
-	int experimental;
+	struct {
+		u8 driver_registered:1;
+		u8 proc_created:1;
+		u8 init_called:1;
+		u8 notify_installed:1;
+		u8 experimental:1;
+	} flags;
 };
 
 struct ibm_init_struct {