sched/doc: supplement CPU capacity with RISC-V

This commit 7d2078310cbf ("dt-bindings: arm: move cpu-capacity to a
shared loation") updates some references about capacity-dmips-mhz
property in this document.

The list of architectures using capacity-dmips-mhz omits RISC-V, so
supplements it here.

Signed-off-by: Song Shuai <[e-mail]>
Reviewed-by: Palmer Dabbelt <[e-mail]> # English
Acked-by: Palmer Dabbelt <[e-mail]>
Reviewed-by: Alex Shi <[e-mail]>
Reviewed-by: Conor Dooley <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/scheduler/sched-capacity.rst

···
 needs to be handed to it. Architectures must define arch_scale_cpu_capacity()
 for that purpose.
 
-The arm and arm64 architectures directly map this to the arch_topology driver
+The arm, arm64, and RISC-V architectures directly map this to the arch_topology driver
 CPU scaling data, which is derived from the capacity-dmips-mhz CPU binding; see
 Documentation/devicetree/bindings/cpu/cpu-capacity.txt.
 

Documentation/translations/zh_CN/scheduler/sched-capacity.rst

···
 当前，Linux无法凭自身算出CPU算力，因此必须要有把这个信息传递给Linux的方式。每个架构必须为此
 定义arch_scale_cpu_capacity()函数。
 
-arm和arm64架构直接把这个信息映射到arch_topology驱动的CPU scaling数据中（译注：参考
+arm、arm64和RISC-V架构直接把这个信息映射到arch_topology驱动的CPU scaling数据中（译注：参考
 arch_topology.h的percpu变量cpu_scale），它是从capacity-dmips-mhz CPU binding中衍生计算
 出来的。参见Documentation/devicetree/bindings/cpu/cpu-capacity.txt。