RISC-V: Detect the Ssqosid extension

Ssqosid is the Supervisor QoS ID extension defined in the RISC-V CBQRI
(Capacity and Bandwidth QoS Register Interface) specification.

Link: https://github.com/riscv-non-isa/riscv-cmqri/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>
---
Note:
- A version of this patch rebased on riscv/for-next was already
  submitted as an RFC to linux-riscv [1] with Message-ID:
    20230410043646.3138446-1-dfustini@baylibre.com
- This patch is included in this RFC series so as to provide a cohesive
  demonstration in one series.

[1] https://lore.kernel.org/lkml/20230410043646.3138446-1-dfustini@baylibre.com/