nouveau: ACPI: Use the ACPI_COMPANION() macro directly

nouveau: ACPI: Use the ACPI_COMPANION() macro directly

The ACPI_HANDLE() macro is a wrapper arond the ACPI_COMPANION()
macro and the ACPI handle produced by the former comes from the
ACPI device object produced by the latter, so it is way more
straightforward to evaluate the latter directly instead of passing
the handle produced by the former to acpi_bus_get_device().

Modify nouveau_acpi_edid() accordingly (no intentional functional
impact).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>