bzip2/lzma: move initrd/ramfs options out of BLK_DEV

Impact: Partial resolution of build failure

Move the initrd/initramfs configuration options from
drivers/block/Kconfig to usr/Kconfig, since they do not and should not
depend on CONFIG_BLK_DEV.  This fixes builds when CONFIG_BLK_DEV=n.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>