Re-use the dev type in device.mli

Plus some minor whitespace fixes

Signed-off-by: John Else <john.else@citrix.com>
CP-6968: Add mechanism for binding PCI devices to the NVIDIA drivers

Signed-off-by: John Else <john.else@citrix.com>
CP-6968: Bind GPUs to the NVIDIA driver when required

When creating a vGPU, make sure the target physical GPU is bound to the
NVIDIA driver first.

Signed-off-by: John Else <john.else@citrix.com>
CP-6968: Add code to allow restarting gpumon from xapi

Signed-off-by: John Else <john.else@citrix.com>
CP-6968: Stop gpumon while VMs with vGPUs are starting

Signed-off-by: John Else <john.else@citrix.com>
Restart gpumon as part of xe-toolstack-restart

Signed-off-by: John Else <john.else@citrix.com>
CP-6968: Lock NVIDIA devices before unbinding

Signed-off-by: John Else <john.else@citrix.com>
Workaround inconsistent device naming

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #1557 from johnelse/cp-6968

Enable switching of pGPUs between vGPU and passthrough mode