net/tls: Remove the __TLS_DEC_STATS() macro.

The commit d26b698d ("net/tls: add skeleton of MIB statistics")
introduced __TLS_DEC_STATS(), but it is not used and __SNMP_DEC_STATS() is
not defined also. Let's remove it.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tls.h

@@ -79,8 +79,6 @@
 	__SNMP_INC_STATS((net)->mib.tls_statistics, field)
 #define TLS_INC_STATS(net, field)				\
 	SNMP_INC_STATS((net)->mib.tls_statistics, field)
-#define __TLS_DEC_STATS(net, field)				\
-	__SNMP_DEC_STATS((net)->mib.tls_statistics, field)
 #define TLS_DEC_STATS(net, field)				\
 	SNMP_DEC_STATS((net)->mib.tls_statistics, field)