arm64: tlb: remove redundant barrier from __flush_tlb_pgtable

__flush_tlb_pgtable is used to invalidate intermediate page table
entries after they have been cleared and are about to be freed. Since
pXd_clear imply memory barriers, we don't need the extra one here.

Reviewed-by: Catalin Marinas <[e-mail]>
Signed-off-by: Will Deacon <[e-mail]>
Signed-off-by: Catalin Marinas <[e-mail]>

arch/arm64/include/asm/tlbflush.h

···
 {
 	unsigned long addr = uaddr >> 12 | (ASID(mm) << 48);
 
-	dsb(ishst);
 	asm("tlbi	vae1is, %0" : : "r" (addr));
 	dsb(ish);
 }