ACPI: Move definition of PREFIX from acpi_bus.h to internal..h

Linux/ACPI core files using internal.h all PREFIX "ACPI: ",
however, not all ACPI drivers use/want it -- and they
should not have to #undef PREFIX to define their own.

Add GPL commment to internal.h while we are there.

This does not change any actual console output,
asside from a whitespace fix.

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/event.c b/drivers/acpi/event.c
index aeb7e5f..c511071bf 100644
--- a/drivers/acpi/event.c
+++ b/drivers/acpi/event.c
@@ -14,6 +14,8 @@
 #include <net/netlink.h>
 #include <net/genetlink.h>
 
+#include "internal.h"
+
 #define _COMPONENT		ACPI_SYSTEM_COMPONENT
 ACPI_MODULE_NAME("event");