tcp: fix the missing avr32 SOF_TIMESTAMPING_OPT_STATS

The commit of SOF_TIMESTAMPING_OPT_STATS didn't include the
new header for avr32, causing build to break. The patch fixes it.

Fixes: 1c885808 ("tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING")
Reported-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/avr32/include/uapi/asm/socket.h

@@ -90,4 +90,6 @@
 
 #define SO_CNX_ADVICE		53
 
+#define SCM_TIMESTAMPING_OPT_STATS	54
+
 #endif /* _UAPI__ASM_AVR32_SOCKET_H */