nodedev: Lock @priv sooner

nodedev: Lock @priv sooner

The nodedev driver private data object @priv is created by
calling udevEventDataNew(). After that, driver->privateData
pointer is set to the freshly allocated object and only a few
lines after all of this the object is locked. Technically it is
safe because there should not be any other thread at this point,
but defensive style of programming says it's better if the object
is locked before driver's privateData is set.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>