softlockup: Documentation/sysctl/kernel.txt: fix softlockup_thresh description

- s/s/seconds/

- s/10 seconds/60 seconds/

- Mention the zero-disables-it feature.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Documentation/sysctl/kernel.txt

@@ -351,9 +351,10 @@ kernel.  This value defaults to SHMMAX.
 
 softlockup_thresh:
 
-This value can be used to lower the softlockup tolerance
-threshold. The default threshold is 10s.  If a cpu is locked up
-for 10s, the kernel complains.  Valid values are 1-60s.
+This value can be used to lower the softlockup tolerance threshold.  The
+default threshold is 60 seconds.  If a cpu is locked up for 60 seconds,
+the kernel complains.  Valid values are 1-60 seconds.  Setting this
+tunable to zero will disable the softlockup detection altogether.
 
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