Fix build system: full commit hash, git clean, remove absent USB BINS from base-initfs

- Use full 40-char commit hash in base recipe.toml so the cookbook's
  caching logic correctly recognizes already-fetched sources (short
  hashes always missed the cache, causing patches to re-apply on top
  of already-patched source).
- Add git clean -fd before git reset --hard in fetch.rs so untracked
  files from previous patch applications are removed before re-patching.
- Remove ehcid/ohcid/uhcid from base-initfs BINS list (same fix as
  base recipe, these drivers don't exist in the current upstream).

With these fixes, redbear-live-mini builds and boots to login prompt in QEMU.

recipes/core/base-initfs/recipe.toml

@@ -35,7 +35,7 @@ virt_bins()
 
 x86_common_bins()
 {
-    BINS+=(ahcid ehcid ohcid uhcid ided ps2d usbhidd usbscsid usbhubd xhcid vesad)
+    BINS+=(ahcid ided ps2d usbhidd usbscsid usbhubd xhcid vesad)
     virt_bins
 }