uml: x86_64 should copy %fs during fork

%fs needs to be copied from parent to child during fork.

Tidied up some whitespace while I was here.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-um/processor-x86_64.h

@@ -37,6 +37,7 @@ static inline void arch_flush_thread(struct arch_thread *thread)
 static inline void arch_copy_thread(struct arch_thread *from,
                                     struct arch_thread *to)
 {
+	to->fs = from->fs;
 }
 
 #include "asm/arch/user.h"