return an error if establishing the interrupt fails
return an error if establishing the interrupt fails

rumpkernel-attic/rumprun-baremetal,ujamjar/rumpuser-baremetal,rumpkernel-attic/rumprun-baremetal,rumpkernel-attic/rumprun-baremetal,ujamjar/rumpuser-baremetal,ujamjar/rumpuser-baremetal