riscv: Move .rela.dyn outside of init to avoid empty relocations

riscv: Move .rela.dyn outside of init to avoid empty relocations

This is a preparatory patch for relocatable kernels: .rela.dyn should be
in .init but doing so actually produces empty relocations, so this should
be a temporary commit until we find a solution.

This issue was reported here [1].

[1] https://lore.kernel.org/all/4a6fc7a3-9697-a49b-0941-97f32194b0d7@ghiti.fr/.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230329045329.64565-3-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>