soc/amd/common/spi: add and use define for last FIFO position

The existing define for SPI_FIFO_DEPTH looked a bit suspicious, but
turned out to be correct.

Change-Id: I91e65d922673f5c451a336ae013cb75f87a3fc98
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42076
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions