accel/amdxdna: Add device status for aie2 devices

Add device status to track if aie2_hw_start() or aie2_hw_stop() is
re-entered. In aie2_hw_stop(), call drmm_kfree to free mbox.

Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241206220001.164049-2-lizhi.hou@amd.com