This function is needed by the network driver in a later commit.
It is useful in functions like networkNotifyActualDevice and
networkReleaseActualDevice

Move the functions the parse/format, and validate PCI addresses to
their own file so they can be conveniently used in other places
besides device_conf.c

Refactoring existing code without causing any functional changes to
prepare for new code.

This patch makes the code reusable.
Signed-off-by: NShradha Shah <sshah@solarflare.com>