Documentation: embargoed-hardware-issues.rst: Add myself for RISC-V

I'm not sure exactly how RISC-V fits into the story here, but I'm happy
to voluteer a sort of catch-all for vendors who aren't otherwise
represented.

Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230912180657.31841-1-palmer@rivosinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>