[PATCH] headers: enable ppc64 ___arch__swab16 and ___arch__swab32

This patch cleans up asm-ppc64/byteorder.h to enable ___arch__swab16 and
___arch__swab32 which are marked TODO currently. It removes ___arch__swab64
because ppc64 does not have short instruction combinations for swab64, the
recent gcc generates enough smart code that is equivalent to hand assembled
code under my tests.

Signed-off-by: GOTO Masanori <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/asm-ppc64/byteorder.h

···
 	__asm__ __volatile__ ("stwbrx %1,0,%2" : "=m" (*addr) : "r" (val), "r" (addr));
 }
 
-#if 0
 static __inline__ __attribute_const__ __u16 ___arch__swab16(__u16 value)
 {
 	__u16 result;
···
 	return result;
 }
 
-static __inline__ __attribute_const__ __u64 ___arch__swab64(__u64 value)
-{
-	__u64 result;
-#error implement me
-}
-
 #define __arch__swab16(x) ___arch__swab16(x)
 #define __arch__swab32(x) ___arch__swab32(x)
-#define __arch__swab64(x) ___arch__swab64(x)
-
-#endif
 
 /* The same, but returns converted value from the location pointer by addr. */
 #define __arch__swab16p(addr) ld_le16(addr)