ACPICA: Fix miscellaneous warnings under gcc 4+

Some possible warnings with gcc 4+, especially with extended warnings
enabled

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpica/dswstate.c b/drivers/acpi/acpica/dswstate.c
index 40f92bf..e46c821 100644
--- a/drivers/acpi/acpica/dswstate.c
+++ b/drivers/acpi/acpica/dswstate.c
@@ -102,7 +102,7 @@
 	/* Return object of the top element and clean that top element result stack */
 
 	walk_state->result_count--;
-	index = walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
+	index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
 
 	*object = state->results.obj_desc[index];
 	if (!*object) {
@@ -186,7 +186,7 @@
 
 	/* Assign the address of object to the top free element of result stack */
 
-	index = walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
+	index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
 	state->results.obj_desc[index] = object;
 	walk_state->result_count++;