soc/amd/{common,cezanne}: Add uPEP device

The uPEP device is required to support S0i3. The device has been written
in ASL to make it easier to read and maintain. The device constraints
are purely informational. We use a dummy constraint like the Intel
platforms to keep both linux and Windows functional.

In order for this device to be used by the linux kernel the
ACPI_FADT_LOW_PWR_IDLE_S0 flag must be set. So including it
unconditionally doesn't cause any problems.

The AMD Modern Standby BIOS Implementation Guide defines two UUIDs,
one for getting the device constraints, and one for handling
notifications. This differs from the Intel specification and the linux
driver implementation. For this reason I haven't implemented any of the
notification callbacks yet.

BUG=b:178728116
TEST=Boot OS and verify _DSM is called:
[    0.226701] lps0_device_attach: ACPI: \_SB_.PEP_: _DSM function mask: 0x3
[    0.226722] lpi_device_get_constraints_amd: ACPI: \_SB_.PEP_: _DSM function 1 eval successful
[    0.226723] lpi_device_get_constraints_amd: ACPI: \_SB_.PEP_: LPI: constraints list begin:
[    0.226724] lpi_device_get_constraints_amd: ACPI: \_SB_.PEP_: LPI: constraints list end

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: I2deef47eabe702efe1a0f3747c9f27bcec37464b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52445
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

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