RISC-V: KVM: Remove redundant includes of asm/kvm_vcpu_timer.h

The asm/kvm_vcpu_timer.h is redundantly included in vcpu_sbi_base.c
so let us remove it.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>