We don't explicitly check for error here and M_WAITOK will just put the
process to sleep waiting on resources to become available.
Suggested by John Baldwin
The driver is in control of the show, so when you try and unload a module
the driver detach routine is called first. It is what drives the whole
unload process and so lots of panics occur if dev->driver is already
free.
me to match other drivers and avoid ifdeffing. The linux via_drv.c will
be moved from shared-core to linux-core soon by repocopy.
Submitted by: Jake Burkholder <jake@FreeBSD.org> Tested by: unichrome