Kconfig: provide MAINBOARD_HAS_TPM_CR50 option

The CR50 TPM can do both SPI and I2C communication. However,
there's situations where policy needs to be applied for CR50
generically regardless of the I/O transport. Therefore add
MAINBOARD_HAS_TPM_CR50 to encompass that.  Additionally,
once the mainboard has selected CR50 TPM automatically select
MAINBOARD_HAS_TPM2 since CR50 TPM is TPM 2.0.

Change-Id: I878f9b9dc99cfb0252d6fef7fc020fa3d391fcec
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/19370
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins)

src/Kconfig

@@ -402,6 +402,12 @@ config TPM2
 
 	  If unsure, say N.
 
+config MAINBOARD_HAS_TPM_CR50
+	bool
+	default y if MAINBOARD_HAS_SPI_TPM_CR50 || MAINBOARD_HAS_I2C_TPM_CR50
+	default n
+	select MAINBOARD_HAS_TPM2
+
 config HEAP_SIZE
 	hex
 	default 0x4000