ACPICA: Fix unresolved name issue for no-debug and no-error-msg cases

The _acpi_module_name was left undefined in these cases, but it
is actually needed as a parameter to some interfaces. Define
_acpi_module_name as a null string in these cases.  Acpica BZ 888.

http://www.acpica.org/bugzilla/show_bug.cgi?id=888Signed-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>

include/acpi/acoutput.h

@@ -183,13 +183,19 @@
 
 #if defined (ACPI_DEBUG_OUTPUT) || !defined (ACPI_NO_ERROR_MESSAGES)
 /*
- * Module name is included in both debug and non-debug versions primarily for
- * error messages. The __FILE__ macro is not very useful for this, because it
- * often includes the entire pathname to the module
+ * The module name is used primarily for error and debug messages.
+ * The __FILE__ macro is not very useful for this, because it
+ * usually includes the entire pathname to the module making the
+ * debug output difficult to read.
  */
 #define ACPI_MODULE_NAME(name)          static const char ACPI_UNUSED_VAR _acpi_module_name[] = name;
 #else
+/*
+ * For the no-debug and no-error-msg cases, we must at least define
+ * a null module name.
+ */
 #define ACPI_MODULE_NAME(name)
+#define _acpi_module_name ""
 #endif
 
 /*