x86, 32-bit: ifdef out struct thread_struct::fs

After commit 464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28 aka
"[PATCH] i386: Convert i386 PDA code to use %fs"
%fs saved during context switch moved from thread_struct to pt_regs
and value on thread_struct became unused.

[ Impact: reduce thread_struct size on 32-bit ]

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: containers@lists.linux-foundation.org
LKML-Reference: <20090503232952.GI16631@x200.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/processor.h

@@ -428,7 +428,9 @@ struct thread_struct {
 	unsigned short		gsindex;
 #endif
 	unsigned long		ip;
+#ifdef CONFIG_X86_64
 	unsigned long		fs;
+#endif
 	unsigned long		gs;
 	/* Hardware debugging registers: */
 	unsigned long		debugreg0;
@@ -874,7 +876,6 @@ static inline void spin_lock_prefetch(const void *x)
 	.vm86_info		= NULL,					  \
 	.sysenter_cs		= __KERNEL_CS,				  \
 	.io_bitmap_ptr		= NULL,					  \
-	.fs			= __KERNEL_PERCPU,			  \
 }
 
 /*