device-types: rk3399-gru-kevin: fix start_message and bootloader_prompt
MR upstream: https://git.lavasoftware.org/lava/lava/-/merge_requests/1757
Signed-off-by: Laura Nao laura.nao@collabora.com
MR upstream: https://git.lavasoftware.org/lava/lava/-/merge_requests/1757
Signed-off-by: Laura Nao laura.nao@collabora.com