staging: greybus: power_supply: fix prop-descriptor request size

Since moving the message buffers off the stack, the dynamically
allocated get-prop-descriptor request buffer is incorrectly sized due to
using the pointer rather than request-struct size when creating the
operation.

Fortunately, the pointer size is always larger than this one-byte
request, but this could still cause trouble on the remote end due to the
unexpected message size.

Fixes: 9d15134d ("greybus: power_supply: rework get descriptors")
Cc: stable <stable@vger.kernel.org>     # 4.9
Cc: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/power_supply.c

@@ -520,7 +520,7 @@ static int gb_power_supply_prop_descriptors_get(struct gb_power_supply *gbpsy)
 
 	op = gb_operation_create(connection,
 				 GB_POWER_SUPPLY_TYPE_GET_PROP_DESCRIPTORS,
-				 sizeof(req), sizeof(*resp) + props_count *
+				 sizeof(*req), sizeof(*resp) + props_count *
 				 sizeof(struct gb_power_supply_props_desc),
 				 GFP_KERNEL);
 	if (!op)