mksdcard.sh: update for Jellybean
bootscript.mk: use Jellybean-specific bootscript for 32bpp
nitrogen6x: use fstab.boundary (to include /boot partition)

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
nitrogen6x: use fstab.boundary (to include /boot partition)

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>