perf sched map: Add support for multiple task names using CSV

perf sched map: Add support for multiple task names using CSV

To track the scheduling patterns of multiple tasks simultaneously,
multiple task names can be specified using a comma separator
without any whitespace.

Sample output for --task-name perf,wdavdaemon
=============
 .  *A0  .   .   .   .   -   .   131040.641346 secs A0 => wdavdaemon:62509
 .   A0 *B0  .   .   .   -   .   131040.641378 secs B0 => wdavdaemon:62274
 .  *-   B0  .   .   .   -   .   131040.641379 secs
*C0  .   B0  .   .   .   .   .   131040.641572 secs C0 => wdavdaemon:62283

...

 .  *-   .   .   .   .   .   .   131041.395649 secs
 .   .   .   .   .   .   .  *X2  131041.403969 secs X2 => perf:70211
 .   .   .   .   .   .   .  *-   131041.404006 secs

Suggested-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-and-tested-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
Cc: Chen Yu <yu.c.chen@intel.com>
Link: https://lore.kernel.org/r/20240707182716.22054-3-vineethr@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>