These net drivers init dev->rmem_start/end but do not use these at all

(probably as a result of copying skeleton or similar).  Removed this as 
a step in the goal to remove rmem_start/end from netdev struct entirely.

drivers/net/3c505.c

@@ -1383,7 +1383,7 @@ static inline void elp_init(struct net_device *dev)
 	/*
 	 * memory information
 	 */
-	dev->mem_start = dev->mem_end = dev->rmem_end = dev->rmem_start = 0;
+	dev->mem_start = dev->mem_end = 0;
 }
 
 /************************************************************

drivers/net/arcnet/arc-rimi.c

@@ -153,8 +153,6 @@ static int __init arcrimi_found(struct net_device *dev)
 
 	dev->mem_start = first_mirror;
 	dev->mem_end = last_mirror + MIRROR_SIZE - 1;
-	dev->rmem_start = dev->mem_start + BUFFER_SIZE * 0;
-	dev->rmem_end = dev->mem_start + BUFFER_SIZE * 2 - 1;
 
 	/* initialize the rest of the device structure. */
 

drivers/net/arcnet/com90xx.c

@@ -447,8 +447,6 @@ static int __init com90xx_found(struct net_device *dev0, int ioaddr, int airq,
 
 	dev->mem_start = first_mirror;
 	dev->mem_end = last_mirror + MIRROR_SIZE - 1;
-	dev->rmem_start = dev->mem_start + BUFFER_SIZE * 0;
-	dev->rmem_end = dev->mem_start + BUFFER_SIZE * 2 - 1;
 
 	/* Initialize the rest of the device structure. */
 	memset(lp, 0, sizeof(struct arcnet_local));