add the new SO_REUSEPORT socket option to mips and powerpc

SO_REUSEPORT implementation was merged in the linux kernel commit
c617f398edd4db2b8567a28e899a88f8f574798d 2013-01-23

arch/mips/bits/socket.h

@@ -36,7 +36,7 @@ struct cmsghdr
 #define SO_PRIORITY     12
 #define SO_LINGER       128
 #define SO_BSDCOMPAT    14
-/* #define SO_REUSEPORT    512 */
+#define SO_REUSEPORT    512
 #define SO_PASSCRED     17
 #define SO_PEERCRED     18
 #define SO_RCVLOWAT     0x1004

arch/powerpc/bits/socket.h

@@ -32,6 +32,7 @@ struct cmsghdr
 #define SO_PRIORITY     12
 #define SO_LINGER       13
 #define SO_BSDCOMPAT    14
+#define SO_REUSEPORT    15
 #define SO_RCVLOWAT     16
 #define SO_SNDLOWAT     17
 #define SO_RCVTIMEO     18