x86: apl: Enable SPI flash in TPL with APL_SPI_FLASH_BOOT

At present, enabling CONFIG_APL_SPI_FLASH_BOOT does not build since SPI
and SPI flash are not enabled for TPL. Add a condition to fix this and
tidy up a build warning in the SPI-flash driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
2 files changed