perf(drm): group dracut_instmods calls

[aafeijoo-suse]

This module loops over many bus devices, and calls dracut_instmods for each
one. E.g., on a Lenovo Thinkpad laptop:

> for i in /sys/bus/{pci/devices,platform/devices,virtio/devices,soc/devices/soc?,vmbus/devices}/*/modalias; do [[ -e $i ]] && [[ -n $(< "$i") ]]  && echo $i; done | wc -l
79

Every call to dracut_instmods spawns a dracut-install process, which in the
previous example means calling dracut-install 79 times using the same
arguments.

If any call to dracut-install fails, dracut continues its execution (even the
errors are not shown, because it's called with --silent). Therefore, let's
take the contents of all the modalias files into an array and call
dracut-install only once, adding also the -o argument, so if any of the
modules cannot be installed, dracut-install does not stop.

Upstream PR dracutdevs#2577 (already merged in the new upstream dracut-ng/dracut-ng@80f2caf)

[aafeijoo-suse]

FTR: https://bugzilla.redhat.com/show_bug.cgi?id=2278534#c12

On the system in question, a 128 core epyc host with a lot of storage on it:

# for i in /sys/bus/{pci/devices,platform/devices,virtio/devices,soc/devices/soc?,vmbus/devices}/*/modalias; do [[ -e $i ]] && [[ -n $(< "$i") ]]  && echo $i; done | wc -l
14540