drivers/spi/spi_flash: Move flash ops to spi_flash_ops structure

Define a new spi_flash_ops structure, move all spi flash operations to
this structure and add a pointer to this structure in struct spi_flash.

BUG=b:38330715

Change-Id: I550cc4556fc4b63ebc174a7e2fde42251fe56052
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/19757
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
15 files changed