spmi: prevent showing the address of spmidev

Creating devices with the address of the container spmidev is not
indicative of the actual hardware device it represents.

Instead use an unique id to indicate the device it represents.

Bug: 28760543
CRs-Fixed: 1024197
Change-Id: Id18e2a19f4fa1249901a3f275defa8f589270d69
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Biswajit Paul <biswajitpaul@codeaurora.org>
(cherry picked from commit 885e478f)