This patch fixes the encoding for INST_RETIRED.PREC_DIST as published by Intel
(download.01.org/perfmon/) for Icelake. The official encoding
is event code 0x00 umask 0x1, a change from Skylake where it was code 0xc0
umask 0x1.

With this patch applied it is possible to run:
$ perf record -a -e cpu/event=0x00,umask=0x1/pp .....

Whereas before this would fail.

To avoid problems with tools which may use the old code, we maintain the old
encoding for Icelake.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211014001214.2680534-1-eranian@google.com