drm: cope with platformdev->id == -1
drm: cope with platformdev->id == -1

If there are not multiple instances of a platform device, the id
should apparently be set to -1.  Which results in a odd looking
bus-id like "platform:foodrm:-1".  Probably we should just treat
this case as id 0.

Signed-off-by: Rob Clark <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@ti.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs