drivers/spi/tpm: provide Kconfig to indicate CR50 usage

Going forward it's important to note when a CR50 is expected
to be present in the system. Additionally, this Kconfig addition
provides symmetry with the equivalent i2c Kconfig option.

BUG=b:35775104

Change-Id: Ifbd42b8a22f407534b23459713558c77cde6935d
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/18680
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins)
2 files changed