clocksource/drivers/timer-riscv: Set CLOCK_EVT_FEAT_C3STOP based on DT

clocksource/drivers/timer-riscv: Set CLOCK_EVT_FEAT_C3STOP based on DT

We should set CLOCK_EVT_FEAT_C3STOP for a clock_event_device only
when riscv,timer-cannot-wake-cpu DT property is present in the RISC-V
timer DT node.

This way CLOCK_EVT_FEAT_C3STOP feature is set for clock_event_device
based on RISC-V platform capabilities rather than having it set for
all RISC-V platforms.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230103141102.772228-4-apatel@ventanamicro.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org>