[POWERPC] Make the hvc_console output buffer size settable

So the iSeries console will be faster since it can send up to 200 bytes at
a time to the Hypervisor.  This only affects the tty part of the console,
the console writes are still in 16 byte lots.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
diff --git a/drivers/char/hvc_iseries.c b/drivers/char/hvc_iseries.c
index 256afc8e5..4747729 100644
--- a/drivers/char/hvc_iseries.c
+++ b/drivers/char/hvc_iseries.c
@@ -221,7 +221,8 @@
 
 	pi = &port_info[vdev->unit_address];
 
-	hp = hvc_alloc(vdev->unit_address, vdev->irq, &hvc_get_put_ops);
+	hp = hvc_alloc(vdev->unit_address, vdev->irq, &hvc_get_put_ops,
+			VIOCHAR_MAX_DATA);
 	if (IS_ERR(hp))
 		return PTR_ERR(hp);
 	pi->hp = hp;