riscv: pass the mm_struct to __sbi_tlb_flush_range

Move the call mm_cpumask from the callers into __sbi_tlb_flush_range to
reduce a bit of duplicate code and prepare for future changes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>