dracut.cmdline.7.asc: update document for rd.memdebug=4

"rd.memdebug=4" is for kernel module memory consumption debugging.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>

dracut.cmdline.7.asc

@@ -187,8 +187,8 @@ It should be attached to any report about dracut problems.
     _/run/initramfs/init.log_.
     If "quiet" is set, it also logs to the console.
 
-**rd.memdebug=[0-3]**::
-    Print memory usage info at various points, set the verbose level from 0 to 3.
+**rd.memdebug=[0-4]**::
+    Print memory usage info at various points, set the verbose level from 0 to 4.
 +    
     Higher level means more debugging output:
 +
@@ -197,6 +197,10 @@ It should be attached to any report about dracut problems.
     1 - partial /proc/meminfo
     2 - /proc/meminfo
     3 - /proc/meminfo + /proc/slabinfo
+    4 - /proc/meminfo + /proc/slabinfo + tracekomem
+        NOTE: tracekomem is a shell script utilizing kernel trace to track
+              the rough total memory consumption of kernel modules during
+              loading. It may override other trace configurations.
 ----
 
 **rd.break**::