gnu: Add u-boot-rockpro64-rk3399
* gnu/packages/bootloaders.scm (u-boot-rockpro64-rk3399): New exported
variable.
(u-boot-2019.10): New variable.
* gnu/bootloader/u-boot.scm (u-boot-rockpro64-rk3399-bootloader): New exported
variable.
(install-rockpro64-rk3399-u-boot): New variable.
* gnu/system/install.scm (rockpro64-installation-os): New exported variable.
Adjusted-by: Vagrant Cascadian <vagrant@debian.org>
Signed-off-by: Caliph Nomble <nomble@palism.com>
Signed-off-by: Vagrant Cascadian <vagrant@debian.org>