arm64: Do not flush the D-cache for anonymous pages

The D-cache on AArch64 is VIPT non-aliasing, so there is no need to
flush it for anonymous pages.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>

arch/arm64/mm/mmu.c

@@ -339,7 +339,6 @@ void __init paging_init(void)
 	bootmem_init();
 
 	empty_zero_page = virt_to_page(zero_page);
-	__flush_dcache_page(empty_zero_page);
 
 	/*
 	 * TTBR0 is only used for the identity mapping at this stage. Make it