FROMLIST: gunyah: vm_mgr: Add VM start/stop

Add ioctl to trigger the start of a Gunyah virtual machine. Subsequent
commits will provide memory to the virtual machine and add ability to
interact with the resources (capabilities) of the virtual machine.
Although start of the virtual machine can be done implicitly on the
first vCPU run for proxy-schedule virtual machines, there is a
non-trivial number of calls to Gunyah: a more precise error can be given
to userspace which calls VM_START without looking at kernel logs because
userspace can detect that the VM start failed instead of "couldn't run
the vCPU".

Bug: 338347082
Link: https://lore.kernel.org/all/20240222-gunyah-v17-10-1e9da6763d38@quicinc.com/


Change-Id: I428db431bb771e790d1ca4b69569f48ae10d2bee
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>