Use binary-deps.d for dracut ramdisks

Instead of hard-coding a list of binaries to include in the dracut
ramdisk, use the existing binary-deps.d functionality to provide a
list.  This will allow other ramdisks (such as discovery) to add
the binaries they need.

Change-Id: Ib7ffa15e08db1cc45e93a8f2a5c01369772c93ff