ip, bridge: document -timestamp option

This patch documents bridge and ip -timestamp option
Signed-off-by: Satish Ashok <sashok@cumulusnetworks.com>

man/man8/bridge.8

@@ -308,6 +308,9 @@ link setting is configured on specified physical device
 .BI master
 link setting is configured on the software bridge (default)
 
+.TP
+.BR "\-t" , " \-timestamp"
+display current time when using monitor option.
 
 .SS bridge link show - list bridge port configuration.
 

man/man8/ip.8

@@ -175,6 +175,10 @@ executes specified command over all objects, it depends if command supports this
 .BR "\-c" , " -color"
 Use color output.
 
+.TP
+.BR "\-t" , " \-timestamp"
+display current time when using monitor option.
+
 .SH IP - COMMAND SYNTAX
 
 .SS