UPSTREAM: arm64: lib: patch in prfm for copy_page if requested

UPSTREAM: arm64: lib: patch in prfm for copy_page if requested

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_benchmark

Signed-off-by: Andrew Pinski <apinski@cavium.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Andrew Pinski <apinski@cavium.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Bug: 30369029
Patchset: kaslr-arm64-4.4

(cherry picked from commit 60e0a09db24adc8809696307e5d97cc4ba7cb3e0)
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Change-Id: I3821a4d3a7b6fd68b4b0aca31478ec960e4e5172