Add extra arch overrides to asm-generic/checksum.h

There are plausible reasons for architectures to provide their own
versions of csum_partial_copy_nocheck and csum_tcpudp_magic.
By protecting these, the architecture can still re-use the
asm-generic checksum.h, instead of copying it.
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/checksum.h

@@ -33,8 +33,10 @@ extern __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum)
 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
 					int len, __wsum sum, int *csum_err);
 
+#ifndef csum_partial_copy_nocheck
 #define csum_partial_copy_nocheck(src, dst, len, sum)	\
 	csum_partial_copy((src), (dst), (len), (sum))
+#endif
 
 /*
  * This is a version of ip_compute_csum() optimized for IP headers,
@@ -63,12 +65,14 @@ csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
 		unsigned short proto, __wsum sum);
 #endif
 
+#ifndef csum_tcpudp_magic
 static inline __sum16
 csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
 		  unsigned short proto, __wsum sum)
 {
 	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 }
+#endif
 
 /*
  * this routine is used for miscellaneous IP-like checksums, mainly