fix: dkms.post_install: optimize code logic

debian/dkms.post_install

@@ -4,16 +4,24 @@ set -e
 base_dir="${PWD%/*}/$kernelver/$arch/module/arch/arm64/boot/dts"
 install_dir="/usr/lib/linux-image-$kernelver"
 
-if [[ ! -e "$install_dir/amlogic/overlays" ]] || [[ "$(readlink "$install_dir/amlogic/overlays")" == "$base_dir/amlogic/overlays" ]] && [[ -d "$install_dir/amlogic" ]]
-then
-    echo "Link $base_dir/amlogic/overlays to $install_dir/amlogic/overlays"
-    rm -f $install_dir/amlogic/overlays
-    ln -s "$base_dir/amlogic/overlays" "$install_dir/amlogic/overlays"
-fi
+for vendor in "rockchip" "amlogic"
+do
+    if [[ ! -L "$install_dir/$vendor" ]] && [[ ! -d "$install_dir/$vendor" ]]
+    then
+        # Vendor not supported by the kernel
+        continue
+    fi
 
-if [[ ! -e "$install_dir/rockchip/overlays" ]] || [[ "$(readlink "$install_dir/rockchip/overlays")" == "$base_dir/rockchip/overlays" ]] && [[ -d "$install_dir/rockchip" ]]
-then
-    echo "Link $base_dir/rockchip/overlays to $install_dir/rockchip/overlays"
-    rm -f $install_dir/rockchip/overlays
-    ln -s "$base_dir/rockchip/overlays" "$install_dir/rockchip/overlays"
-fi
+    if [[ -e "$install_dir/$vendor/overlays" ]] && [[ ! -L "$install_dir/$vendor/overlays" ]]
+    then
+        # The kernel already comes with overlays.
+        continue
+    fi
+
+    if [[ ! "$(readlink "$install_dir/$vendor/overlays")" == "$base_dir/$vendor/overlays" ]]
+    then
+        echo "Link $base_dir/$vendor/overlays to $install_dir/$vendor/overlays"
+        rm -f $install_dir/$vendor/overlays
+        ln -s "$base_dir/$vendor/overlays" "$install_dir/$vendor/overlays"
+    fi
+done