ACPICA: remove duplicate u8 typedef

During commit e252652f ("ACPICA: acpidump: Remove integer types
translation protection.") two 'unsigned char' types got converted to 'u8'.

The result does not compile with gcc-4.5, it can not cope with duplicate
typedefs.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/actypes.h

@@ -123,7 +123,6 @@
 
 #ifndef ACPI_USE_SYSTEM_INTTYPES
 
-typedef unsigned char u8;
 typedef unsigned char u8;
 typedef unsigned short u16;
 typedef short s16;