ACPI: debug: Remove the not used function

The inline function __acpi_aml_opened() is not used anywhere,
remove it.
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_dbg.c

@@ -117,13 +117,6 @@ static inline bool __acpi_aml_busy(void)
 	return false;
 }
 
-static inline bool __acpi_aml_opened(void)
-{
-	if (acpi_aml_io.flags & ACPI_AML_OPEN)
-		return true;
-	return false;
-}
-
 static inline bool __acpi_aml_used(void)
 {
 	return acpi_aml_io.usages ? true : false;