It has been reported that usage of memcpy() to/from an iomem mapping is invalid,
and a recent arm64 memcpy update [1] triggers a memory abort when dram-access-quirk
is used on the G12A/G12B platforms.

This adds a local sg_copy_to_buffer which makes usage of io versions of memcpy
when dram-access-quirk is enabled.

[1] 28513304 ("arm64: Import latest memcpy()/memmove() implementation")

Fixes: acdc8e71 ("mmc: meson-gx: add dram-access-quirk")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20210609150230.9291-1-narmstrong@baylibre.com
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>