ARM: mm: remove redundant dsb() prior to range TLB invalidation

The kernel TLB range invalidation functions already contain dsb
instructions before and after the maintenance, so there is no need to
introduce additional barriers.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm/mm/dma-mapping.c

@@ -455,7 +455,6 @@ static void __dma_remap(struct page *page, size_t size, pgprot_t prot)
 	unsigned end = start + size;
 
 	apply_to_page_range(&init_mm, start, size, __dma_update_pte, &prot);
-	dsb();
 	flush_tlb_kernel_range(start, end);
 }