Concatenating strings is not a very efficient approach. And in this case fully
unnecessary. We also need some rules to make use of those hwdb entries.
PCI needs to be 8 characters, not 4. And we need to use uppercase hexadecimal
for both. With udev rules this made no difference, but hwdb match is case
sensitive.
Fixes#16119.
This change is only about the source tree. We have tmpfiles.d/, modprobe.d/,
sysctl.d/, and sysusers.d/, but for historical reasons, rules/ didn't fit this
pattern. We also *install* it as rules.d/. Let's rename to be consistent.
Alec Moskvin