Write access is required for some RSMI services. This change
temporarily permits write access so configuration can be done,
and then turns it off.
To help with this, the ScopedCapability struct is introduced to
provide scope limited access, helping to ensure a process is not
left with extra capability, should an exception occur.
Change-Id: I4978a1a688db935b8bfc27b3b537a0dd07959d3f
[ROCm/rdc commit: 6b5aeaaa23]
Chris Freehill
8b1c887834