rtla: Fix the help text in osnoise and timerlat top tools

The help text in osnoise top and timerlat top had some minor errors
and omissions. The -d option was missing the 's' (second) abbreviation and
the error message for '-d' used '-D'.

Cc: stable@vger.kernel.org
Fixes: 1eceb2fc ("rtla/osnoise: Add osnoise top mode")
Fixes: a828cd18 ("rtla: Add timerlat tool and timelart top mode")
Link: https://lore.kernel.org/20240813155831.384446-1-ezulian@redhat.com


Suggested-by: Tomas Glozar <tglozar@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Eder Zulian <ezulian@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>