Fix powerpc32 "set but not used" warnings from INTERNAL_SYSCALL_DECL

[David Miller]

From: "Joseph S. Myers" <joseph@codesourcery.com>
Date: Tue, 4 Dec 2012 00:04:19 +0000

> Building for powerpc32 produces large numbers of "set but not used"
> warnings for variables declared with INTERNAL_SYSCALL_DECL, where the
> combination of macros used ends up not checking anything stored in
> that variable.  As with other architectures that declare a variable
> (rather than nothing) with this macro, it seems appropriate to avoid
> these warnings by using __attribute__ ((unused)), which this patch
> does.
> 
> 2012-12-03  Joseph Myers  <joseph@codesourcery.com>
> 
> 	* sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
> 	(INTERNAL_SYSCALL_DECL): Use __attribute__ ((unused)).

This is fine.