fix(man): default value of rd.retry was increased to 180 seconds

The man page still states the old value of 30 seconds,
which does not reflect the current situation of 180 seconds.

man/dracut.cmdline.7.asc

@@ -151,7 +151,7 @@ Misc
 
 **rd.retry=**__<seconds>__::
     specify how long dracut should retry the initqueue to configure devices.
-    The default is 30 seconds. After 2/3 of the time, degraded raids are force
+    The default is 180 seconds. After 2/3 of the time, degraded raids are force
     started. If you have hardware, which takes a very long time to announce its
     drives, you might want to extend this value.