[tokenring olympic] use memset_io to fix certain platforms

Prefer a single memset_io() to buggy writel/writew/writeb loops.

Bug found and fixed by IBM.

drivers/net/tokenring/olympic.c

@@ -468,14 +468,7 @@ static int olympic_open(struct net_device *dev)
 	printk("Before the open command \n");
 #endif	
 	do {
-		int i;
-
-		for(i=0;i<SRB_COMMAND_SIZE;i+=4)
-			writel(0,init_srb+i);
-		if(SRB_COMMAND_SIZE & 2)
-			writew(0,init_srb+(SRB_COMMAND_SIZE & ~3));
-		if(SRB_COMMAND_SIZE & 1)
-			writeb(0,init_srb+(SRB_COMMAND_SIZE & ~1));
+		memset_io(init_srb,0,SRB_COMMAND_SIZE);
 
 		writeb(SRB_OPEN_ADAPTER,init_srb) ; 	/* open */
 		writeb(OLYMPIC_CLEAR_RET_CODE,init_srb+2);