rootfs(policy): remove Debian-specific DTB injection from generic rootfs builder

Context
- The script carried a platform-specific Debian path that:
  - searched for `glymur-crd.dtb`,
  - created `/boot/dtb` symlink,
  - patched `grub.cfg` to inject `devicetree` directives.
- This behavior is board-specific policy, not generic rootfs assembly responsibility.

Implementation
- Remove the Debian-only DTB injection block entirely, including conditional guard,
  filesystem probing, symlink synthesis, and GRUB mutation.

Architectural rationale
- Keep `build-rootfs.sh` focused on distribution-agnostic image construction.
- Avoid embedding platform policy and hardcoded DTB assumptions in a shared reusable tool.
- Defer DTB/boot policy to dedicated metadata/build layers that own board-specific behavior.

Operational impact
- Reduces implicit side effects in generated GRUB config.
- Improves portability and maintainability of rootfs construction across product lines.

Signed-off-by: Bjordis Collaku <bcollaku@qti.qualcomm.com>

Author: bjordiscollaku

rootfs/scripts/build-rootfs.sh

@@ -675,32 +675,6 @@ sed -i 's/search --no-floppy --fs-uuid --set=root .*/search --no-floppy --label
 # conflicts with our 'root=LABEL=system' argument.
 sed -i 's/root=\/dev\/[^ ]* //g' /boot/grub/grub.cfg
 
-# ==============================================================================
-# Device Tree Configuration for Debian platforms
-# ==============================================================================
-
-if [ "\${distro_lc}" = "debian" ]; then
-    echo '[INFO][CHROOT] Debian target detected. Configuring platform Device Tree...'
-
-    # Locate the platform Device Tree Blob (DTB) in standard library or firmware paths
-    DTB_PATH=\$(find /usr/lib /lib/firmware -name "glymur-crd.dtb" -print -quit)
-
-    if [ -n "\$DTB_PATH" ]; then
-        echo "[INFO][CHROOT] Platform DTB resolved: \$DTB_PATH"
-        
-        # Ensure DTB is accessible in the bootloader's filesystem scope
-        ln -sf "\$DTB_PATH" /boot/dtb
-        
-        # Inject the devicetree directive into the generated GRUB configuration.
-        # This appends the command immediately following the 'initrd' load.
-        sed -i "/^[[:space:]]*initrd/a \    devicetree /boot/dtb" /boot/grub/grub.cfg
-        
-        echo '[SUCCESS][CHROOT] Device Tree directive injected into /boot/grub/grub.cfg'
-    else
-        echo '[WARN][CHROOT] Target DTB (glymur-crd.dtb) not found. Skipping injection.'
-    fi
-fi
-
 echo '[CHROOT] Capturing post-install package list...'
 dpkg-query -W -f='\${Package} \${Version}\n' > /tmp/\${CODENAME}_post.manifest