Update config files. (CONFIG_EFIVAR_FS=m)

Due to systemd can auto-load efivarfs.ko, so wet CONFIG_EFIVAR_FS to
module on x86_64.
Update vanilla config files: enable console rotation

It's enabled in all other kernel flavors so it should be enabled in
vanilla too.
Btrfs: do not bug_on if we try to cow a free space cache inode
(bnc#863235).