procfs: do not force loading of usbcore module
procfs: do not force loading of usbcore module

It appears that the only reason we were force loading the usbcore
module was to facilitate mounting usbfs. Since we no longer mount
usbfs, this is no longer necessary.

X-Gentoo-Bug: 480312
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=480312

OpenRC/openrc,OpenRC/openrc,williamh/openrc,dwfreed/openrc,dwfreed/openrc,williamh/openrc,OpenRC/openrc,dwfreed/openrc,williamh/openrc