perf jevents metric: Fix type of strcmp_cpuid_str

The parser wraps all strings as Events, so the input is an
Event. Using a string would be bad as functions like Simplify are
called on the arguments, which wouldn't be present on a string.

Fixes: 9d5da30e4ae9 ("perf jevents: Add a new expression builtin strcmp_cpuid_str()")
Signed-off-by: Ian Rogers <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: John Garry <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/pmu-events/metric.py

···
   # pylint: disable=invalid-name
   return Function('has_event', event)
 
-def strcmp_cpuid_str(event: str) -> Function:
+def strcmp_cpuid_str(cpuid: Event) -> Function:
   # pylint: disable=redefined-builtin
   # pylint: disable=invalid-name
-  return Function('strcmp_cpuid_str', event)
+  return Function('strcmp_cpuid_str', cpuid)
 
 class Metric:
   """An individual metric that will specifiable on the perf command line."""