Fix e100 net driver typo, from last change.

Contributor: Eli Kupermann @ Intel

drivers/net/e100/e100_eeprom.c

@@ -261,7 +261,7 @@ eeprom_address_size(u16 size)
 {
 	int isize = size;
 	
-	return ffs(isize);
+	return (ffs(isize) - 1);
 }
 
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