opensbi: add package for RISC-V
OpenSBI is a form of a first-stage bootloader, which initializes
certain parts of an SoC and then passes on control to the second
stage bootloader i.e. an u-boot image.
We're introducing the package with release v1.2, which provides
SBI v0.3 and the SBI SRST extensions which helps to gracefully
reboot/shutdown various HiFive-U SoCs.
Tested on SiFive Unleashed and Unmatched boards.
Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu>
(cherry picked from commit
944b13b3ee1d89e11a0121fbeeaa465ab1e25c3c)