On ThunderX T88 pass 1 and pass 2, there is no hardware prefetching so
we need to patch in explicit software prefetching instructions

Prefetching improves this code by 60% over the original code and 2x
over the code without prefetching for the affected hardware using the
benchmark code at https://github.com/apinski-cavium/copy_page_benchmarkSigned-off-by: NAndrew Pinski <apinski@cavium.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Tested-by: NAndrew Pinski <apinski@cavium.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>