vTPM: fix memory allocation flag for rtce buffer at kernel boot

At ibm vtpm initialzation, tpm_ibmvtpm_probe() registers its interrupt
handler, ibmvtpm_interrupt, which calls ibmvtpm_crq_process to allocate
memory for rtce buffer.  The current code uses 'GFP_KERNEL' as the
type of kernel memory allocation, which resulted a warning at
kernel/lockdep.c.  This patch uses 'GFP_ATOMIC' instead so that the
allocation is high-priority and does not sleep.

Cc: stable@kernel.org
Signed-off-by: Hon Ching(Vicky) Lo <honclo@linux.vnet.ibm.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>

drivers/char/tpm/tpm_ibmvtpm.c

@@ -491,7 +491,7 @@ static void ibmvtpm_crq_process(struct ibmvtpm_crq *crq,
 			}
 			ibmvtpm->rtce_size = be16_to_cpu(crq->len);
 			ibmvtpm->rtce_buf = kmalloc(ibmvtpm->rtce_size,
-						    GFP_KERNEL);
+						    GFP_ATOMIC);
 			if (!ibmvtpm->rtce_buf) {
 				dev_err(ibmvtpm->dev, "Failed to allocate memory for rtce buffer\n");
 				return;