RISC-V: Detect the Ssqosid extension

Detect the Ssqosid extension (Supervisor-mode Quality of Service ID) as
defined in the CBQRI (Capacity and Bandwidth QoS Register Interface)
specification.

Link: https://github.com/riscv-non-isa/riscv-cbqri/blob/main/riscv-cbqri.pdf


Signed-off-by: Kornel Dulęba <mindal@semihalf.com>
[dfustini: rebase from v6.0 to v6.3]
Signed-off-by: Drew Fustini <dfustini@baylibre.com>