tools/rtla: Improve exception handling in timerlat_load.py

tools/rtla: Improve exception handling in timerlat_load.py

The enhancements made to timerlat_load.py are intended to improve the script's exception handling.

Summary of the changes:
  - Specific exceptions are now caught for CPU affinity and priority
    settings, with clearer error messages provided.
  - The timerlat file descriptor opening now includes handling for
    PermissionError and OSError, with informative messages.
  - In the infinite loop, generic exceptions have been replaced with
    specific types like KeyboardInterrupt and IOError, improving feedback.

 Before:
    $ sudo python timerlat_load.py 122
    Error setting affinity
 After:
    $ sudo python timerlat_load.py 122
    Error setting affinity: [Errno 22] Invalid argument

 Before:
    $ sudo python timerlat_load.py 1 -p 950
    Error setting priority
 After:
    $ sudo python timerlat_load.py 1 -p 950
    Error setting priority: [Errno 22] Invalid argument

 Before:
    $ python timerlat_load.py 1
    Error opening timerlat fd, did you run timerlat -U?
 After:
    $ python timerlat_load.py 1
    Permission denied. Please check your access rights.

Cc: "lgoncalv@redhat.com" <lgoncalv@redhat.com>
Cc: "jkacur@redhat.com" <jkacur@redhat.com>
Link: https://lore.kernel.org/Q_k1s4hBtUy2px8ou0QKenjEK2_T_LoV8IxAE79aBakBogb-7uHp2fpET3oWtI1t3dy8uKjWeRzQOdKNzIzOOpyM4OjutJOriZ9TrGY6b-g=@protonmail.com
Signed-off-by: Furkan Onder <furkanonder@protonmail.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>