fix(man): correct typo

Author: aafeijoo-suse

man/dracut.cmdline.7.asc

@@ -740,7 +740,7 @@ NFS
     Default is 1.
 
 **rd.net.timeout.dhcp=**__<arg>__::
-    If this option is set, dhclient is called with "-timeout <arg>".
+    If this option is set, dhclient is called with "--timeout <arg>".
 
 **rd.net.timeout.iflink=**__<seconds>__::
     Wait <seconds> until link shows up. Default is 60 seconds.