drivers/i2c/tpm: Remove vendor.irq

The vendor.irq field was originally intended for use as the TPM 1.2
"command complete" interrupt.  However, all actual coreboot tpm drivers
and hardware use the vendor.status method of checking command completion
instead, and this irq field is not used.

Let's just remove this unused functionality to simplify the code.

BRANCH=none
BUG=b:36786804
TEST=Boot reef w/ serial enabled firmware, verify verstage sees
    "cr50 TPM" and does not complain about lack of tis_plat_irq_status().
TEST=Boot eve w/ serial enabled firmware, verify verstage sees
    "cr50 TPM" and does not complain about lack of tis_plat_irq_status().

Change-Id: I994c5bfbd18124af9cb81d9684117af766ab0124
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-on: https://review.coreboot.org/19396
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

src/drivers/i2c/tpm/tis.c

@@ -103,9 +103,6 @@ static ssize_t tpm_transmit(const uint8_t *sbuf, size_t sbufsiz, void *rbuf,
 		goto out;
 	}
 
-	if (chip->vendor.irq)
-		goto out_recv;
-
 	int timeout = 2 * 60 * 1000; /* two minutes timeout */
 	while (timeout) {
 		ASSERT(chip->vendor.status);

src/drivers/i2c/tpm/tpm.c

@@ -545,9 +545,6 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned int bus, uint32_t dev_addr)
 	chip->vendor.send = &tpm_tis_i2c_send;
 	chip->vendor.cancel = &tpm_tis_i2c_ready;
 
-	/* Disable interrupts (not supported) */
-	chip->vendor.irq = 0;
-
 	if (request_locality(chip, 0) != 0)
 		return -1;
 

src/drivers/i2c/tpm/tpm.h

@@ -58,7 +58,6 @@ struct tpm_vendor_specific {
 	uint8_t req_complete_mask;
 	uint8_t req_complete_val;
 	uint8_t req_canceled;
-	int irq;
 	int (*recv)(struct tpm_chip *, uint8_t *, size_t);
 	int (*send)(struct tpm_chip *, uint8_t *, size_t);
 	void (*cancel)(struct tpm_chip *);