[PATCH v2 1/3] decompressors: Update xz to include ARM64 BCJ decoder

[Jules Maselbas]

> +config XZ_DEC_ARM64
> +	bool "ARM64 BCJ filter decoder"
I've just noticied that this string makes this config entry visible
in menuconfig, while all others are not.
It should be only: `bool` without anything else afterward.

cheers
Jules