rtla/osnoise: Fix error message when failing to enable trace instance

rtla/osnoise: Fix error message when failing to enable trace instance

When a trace instance creation fails, tools are printing:

	Could not enable -> osnoiser <- tracer for tracing

Print the actual (and correct) name of the tracer it fails to enable.

Link: https://lkml.kernel.org/r/53ef0582605af91eca14b19dba9fc9febb95d4f9.1645206561.git.bristot@kernel.org
Fixes: b1696371d865 ("rtla: Helper functions for rtla")
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>