dm500hd/dm800se defconfig: build some filesystems as modules

When the kernel size gets over some magical limit,
the dm500hd/dm800se fail to boot it.

Save some size, so we can safely enable UBI support
linux-dreambox: disable flash BBT and use zlib on 64MB nand

-flash based BBT has no advantage on such a small nand chip
-UBIFS space (zlib) is a bigger concern than speed (lzo), on 64MB devices
dreambox-nand-64mb: compensate for larger flash size

claim the PEB's which were used by the BBT
apply dvb_usb_disable_rc_pooling patch for dreamboxes

Signed-off-by: pieterg <pieterg@users.sourceforge.net>
busybox: add OOB support to nandwrite
dreambox-secondstage: use busybox flash_eraseall/nandwrite

We no longer need mtd-utils, saving a bit of image size.
However, keep using mtd-utils flash_erase/nandwrite,
when they are installed.
Silently fallback to busybox applets when they are not.
dreambox-nand-64mb: use minimum journal size (4MB)

Though it saves us only ~70kB, there is no need
to have a 7MB journal in a 55MB partition.
Merge remote-tracking branch 'openpli3/master' into HEAD

Conflicts:
	meta-openpli/recipes-core/busybox/busybox_1.19.4.bbappend