RISC-V: KVM: Remove scounteren initialization

RISC-V: KVM: Remove scounteren initialization

Scounteren CSR controls the direct access the hpmcounters and cycle/
instret/time from the userspace. It's the supervisor's responsibility
to set it up correctly for it's user space. They hypervisor doesn't
need to decide the policy on behalf of the supervisor.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20250515-fix_scounteren_vs-v3-1-729dc088943e@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>