scripts/gdb/tasks: add headers and improve spacing format

With the patch.
<e.g. o/p>
      TASK          PID    COMM
0xffffffff82c2b8c0   0   swapper/0
0xffff888a0ba20040   1   systemd
0xffff888a0ba24040   2   kthreadd
0xffff888a0ba28040   3   rcu_gp

w/o
0xffffffff82c2b8c0 <init_task> 0 swapper/0
0xffff888a0ba20040 1 systemd
0xffff888a0ba24040 2 kthreadd
0xffff888a0ba28040 3 rcu_gp

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Link: http://lkml.kernel.org/r/54c868c79b5fc364a8be7799891934a6fe6d1464.1597742951.git.riteshh@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: riteshharjani

scripts/gdb/linux/tasks.py

@@ -73,11 +73,12 @@ def __init__(self):
         super(LxPs, self).__init__("lx-ps", gdb.COMMAND_DATA)
 
     def invoke(self, arg, from_tty):
+        gdb.write("{:>10} {:>12} {:>7}\n".format("TASK", "PID", "COMM"))
         for task in task_lists():
-            gdb.write("{address} {pid} {comm}\n".format(
-                address=task,
-                pid=task["pid"],
-                comm=task["comm"].string()))
+            gdb.write("{} {:^5} {}\n".format(
+                task.format_string().split()[0],
+                task["pid"].format_string(),
+                task["comm"].string()))
 
 
 LxPs()