init.insmod.*.cfg: Migrate from insmod to modprobe

modprobe is smarter about locating .ko files if they are stored in
subdirectories. For example, it finds heatmap.ko regardless of whether
it's stored in /vendor/lib/modules/heatmap.ko or
/vendor/lib/modules/extra/heatmap.ko.  modprobe also loads all
dependencies automatically.  Let's migrate from insmod to modprobe.

Bug: 185184472
Change-Id: I439fdc76fb6211b416541256c92169da12b0100d