Enforce similar cgroup replacement pattern across OSes, fix lint naming

Signed-off-by: Derek Nola <derek.nola@suse.com>

roles/raspberrypi/tasks/prereq/Raspbian.yml

@@ -2,11 +2,11 @@
 - name: Check if /boot/firmware/cmdline.txt exists
   ansible.builtin.stat:
     path: /boot/firmware/cmdline.txt
-  register: boot_firmware_cmdline_txt
+  register: raspberrypi_boot_file
 
 - name: Enable cgroup via boot commandline if not already enabled
   ansible.builtin.replace:
-    path: "{{ (boot_firmware_cmdline_txt.stat.exists) | ternary('/boot/firmware/cmdline.txt', '/boot/cmdline.txt') }}"
+    path: "{{ (raspberrypi_boot_file.stat.exists) | ternary('/boot/firmware/cmdline.txt', '/boot/cmdline.txt') }}"
     regexp: '^([\w](?!.*\b{{ cgroup_item }}\b).*)$'
     replace: '\1 {{ cgroup_item }}'
   loop:
@@ -41,10 +41,8 @@
       community.general.alternatives:
         path: /usr/sbin/iptables-legacy
         name: iptables
-      register: ip4_legacy
 
     - name: Changing to ip6tables-legacy
       community.general.alternatives:
         path: /usr/sbin/ip6tables-legacy
         name: ip6tables
-      register: ip6_legacy