net: cleanup unused macros in net directory

Clean up some unused macros in net/*.
1. be left for code change. e.g. PGV_FROM_VMALLOC, PGV_FROM_VMALLOC, KMEM_SAFETYZONE.
2. never be used since introduced to kernel.
   e.g. P9_RDMA_MAX_SGE, UTIL_CTRL_PKT_SIZE.

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Acked-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/rds.h

@@ -50,7 +50,6 @@ rdsdebug(char *fmt, ...)
 #define RDS_FRAG_SIZE	((unsigned int)(1 << RDS_FRAG_SHIFT))
 
 #define RDS_CONG_MAP_BYTES	(65536 / 8)
-#define RDS_CONG_MAP_LONGS	(RDS_CONG_MAP_BYTES / sizeof(unsigned long))
 #define RDS_CONG_MAP_PAGES	(PAGE_ALIGN(RDS_CONG_MAP_BYTES) / PAGE_SIZE)
 #define RDS_CONG_MAP_PAGE_BITS	(PAGE_SIZE * 8)