fast_spi: Copy mmio flash to cache when reading

The flash_rewrite operation modifies the contents read from flash_read
in place so copy the data to the cache before returning from
fast_spi_flash_read

BUG=b:124297157
TEST=Tested setting vendor data on arcada
BRANCH=none

Change-Id: I37dbd6fa3899322ce0b52dbd39c3ab9b68dca13c
Signed-off-by: Mathew King <mathewk@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1552021
Reviewed-by: Julius Werner <jwerner@chromium.org>
1 file changed