This patch enables I/O stacks to IIO PMON mapping on Icelake server.

Mapping of IDs in SAD_CONTROL_CFG notation to IDs in PMON notation for
Icelake server:

Stack Name         | CBDMA/DMI | PCIe_1 | PCIe_2 | PCIe_3 | PCIe_4 | PCIe_5
SAD_CONTROL_CFG ID |     0     |    1   |    2   |    3   |    4   |    5
PMON ID            |     5     |    0   |    1   |    2   |    3   |    4

I/O stacks to IIO PMON mapping is exposed through attributes
/sys/devices/uncore_iio_<pmu_idx>/dieX, where dieX is file which holds
"Segment:Root Bus" for PCIe root port which can be monitored by that
IIO PMON block. Example for 2-S Icelake server:

==> /sys/devices/uncore_iio_0/die0 <==
0000:16
==> /sys/devices/uncore_iio_0/die1 <==
0000:97
==> /sys/devices/uncore_iio_1/die0 <==
0000:30
==> /sys/devices/uncore_iio_1/die1 <==
0000:b0
==> /sys/devices/uncore_iio_3/die0 <==
0000:4a
==> /sys/devices/uncore_iio_3/die1 <==
0000:c9
==> /sys/devices/uncore_iio_4/die0 <==
0000:64
==> /sys/devices/uncore_iio_4/die1 <==
0000:e2
==> /sys/devices/uncore_iio_5/die0 <==
0000:00
==> /sys/devices/uncore_iio_5/die1 <==
0000:80
Signed-off-by: Alexander Antonov <alexander.antonov@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lkml.kernel.org/r/20210426131614.16205-4-alexander.antonov@linux.intel.com