accel/ivpu: Disable buttress on device removal

Use pci_set_power_state() to disable buttress when device is removed.
This is workaround of hardware bug that hangs the system.

Additionally not disabling buttress prevents CPU enter deeper Pkg-C
states when the driver is unloaded or fail to probe.

Fixes: 35b13763 ("accel/ivpu: Introduce a new DRM driver for Intel VPU")
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230323125504.2586442-6-stanislaw.gruszka@linux.intel.com