kernel/arch/elf: implement for riscv64

Change-Id: I919ee4883af780f48385a53e5768eba35dde6423
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4054
Reviewed-by: X512 <danger_mail@list.ru>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>

kernel/arch/riscv64: Fix elf image loading / add basic relocations

Change-Id: I0f24ef2585ae9f83a8cff8c145276d54298d1c6b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3677
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

riscv64: Fill in more bulk architecture items around libroot/kernel

Change-Id: Ia2a86d8814d06950ea2d2d19d966c642d26f81d6
Reviewed-on: https://review.haiku-os.org/c/1302
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>