ACPICA: Re-implement interpreters' "serialized mode"

Enhanced the implementation of the interpreters'
serialized mode (boot with "acpi_serialize" to set
acpi_glb_all_methods_serialized flag.)
When this mode is specified, instead of creating a serialization
semaphore per control method, the interpreter lock is
simply no longer released before a blocking operation
during control method execution. This effectively makes
the AML Interpreter single-threaded. The overhead of a
semaphore per-method is eliminated.

Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/namespace/nsinit.c b/drivers/acpi/namespace/nsinit.c
index aec8488..0d3a42b 100644
--- a/drivers/acpi/namespace/nsinit.c
+++ b/drivers/acpi/namespace/nsinit.c
@@ -213,7 +213,7 @@
 			u32 level, void *context, void **return_value)
 {
 	acpi_object_type type;
-	acpi_status status;
+	acpi_status status = AE_OK;
 	struct acpi_init_walk_info *info =
 	    (struct acpi_init_walk_info *)context;
 	struct acpi_namespace_node *node =
@@ -267,10 +267,7 @@
 	/*
 	 * Must lock the interpreter before executing AML code
 	 */
-	status = acpi_ex_enter_interpreter();
-	if (ACPI_FAILURE(status)) {
-		return (status);
-	}
+	acpi_ex_enter_interpreter();
 
 	/*
 	 * Each of these types can contain executable AML code within the