Rather than using the streaming API, use the coherent allocator to
provide this memory, thereby eliminating cache flushing of it each
time we map and unmap it.  This results in a 7.5% increase in
transfer speed with a UHS-1 card operating in 3.3v mode at a clock
of 49.5MHz.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: NMarkus Pargmann <mpa@pengutronix.de>
Tested-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NChris Ball <chris@printf.net>