soc/amd/stoneyridge: Enable SPI writes

- Change soc/amd/stoneyridge/Kconfig to set BOOT_DEVICE_SUPPORTS_WRITES

BUG=b:65485690
TEST=Build & boot kahlee.

Change-Id: I595a27ac27daa42c2499de1a343bc30be9a89fa6
Signed-off-by: John E. Kabat Jr <john.kabat@scarletltd.com>
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: https://review.coreboot.org/22636
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2 files changed