input: remove f_version abuse

input: remove f_version abuse

f_version is removed from struct file. Make input stop abusing f_version
for stashing information for poll. Move the input state counter into
input_seq_state and allocate it via seq_private_open() and free via
seq_release_private().

Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-12-6d3e4816aa7b@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>