perf vendor events intel: Update icelake events to v1.21

perf vendor events intel: Update icelake events to v1.21

Update icelake events to v1.21 released in:
https://github.com/intel/perfmon/commit/54f1246b0496112c1d2b2a49e4859c85caa3dbf4

Improves descriptions, removes TOPDOWN.BR_MISPREDICT_SLOTS.

Event json automatically generated by:
https://github.com/intel/perfmon/blob/main/scripts/create_perf_json.py

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Edward Baker <edward.baker@intel.com>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Samantha Alt <samantha.alt@intel.com>
Cc: Weilin Wang <weilin.wang@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240214011820.644458-8-irogers@google.com