tpm: interrupt clear fix

Under stress testing I found that the interrupt is not always cleared.
This is a bug and this patch should go into 2.6.18 and 2.6.17.x.
Signed-off-by: Kylene Hall <kjhall@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/char/tpm/tpm_tis.c

@@ -424,6 +424,7 @@ static irqreturn_t tis_int_handler(int irq, void *dev_id, struct pt_regs *regs)
 	iowrite32(interrupt,
 		  chip->vendor.iobase +
 		  TPM_INT_STATUS(chip->vendor.locality));
+	ioread32(chip->vendor.iobase + TPM_INT_STATUS(chip->vendor.locality));
 	return IRQ_HANDLED;
 }