kernel: fix framebuffer console after 6.6

These options were already enabled in previous versions, but Kconfig
changes in 6.6 made NixOS kernel disable them. Therefore, we enable
unconditionally, to be explicit that they're needed.
Without them, the fbcon/console on systems with DRM devices freeze/blank
on early boot, even though the system boots normally.

pkgs/os-specific/linux/kernel/common-config.nix

···
       FRAMEBUFFER_CONSOLE = yes;
       FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER = yes;
       FRAMEBUFFER_CONSOLE_ROTATION = yes;
+      FRAMEBUFFER_CONSOLE_DETECT_PRIMARY = yes;
       FB_GEODE            = mkIf (stdenv.hostPlatform.system == "i686-linux") yes;
       # On 5.14 this conflicts with FB_SIMPLE.
       DRM_SIMPLEDRM = whenAtLeast "5.14" no;
+      DRM_FBDEV_EMULATION = yes;
     };
 
     fonts = {