riscv: cleanup riscv_cpuid_to_hartid_mask

Move the initial clearing of the mask from the callers to
riscv_cpuid_to_hartid_mask, and remove the unused !CONFIG_SMP stub.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>

arch/riscv/include/asm/tlbflush.h

@@ -47,7 +47,6 @@ static inline void remote_sfence_vma(struct cpumask *cmask, unsigned long start,
 {
 	struct cpumask hmask;
 
-	cpumask_clear(&hmask);
 	riscv_cpuid_to_hartid_mask(cmask, &hmask);
 	sbi_remote_sfence_vma(hmask.bits, start, size);
 }