rpmsg: glink: use only lower 16-bits of param2 for CMD_OPEN name length

The name len field of the CMD_OPEN packet is only 16-bits and the upper
16-bits of "param2" are a different "prio" field, which can be nonzero in
certain situations, and CMD_OPEN packets can be unexpectedly dropped
because of this.

Fix this by masking out the upper 16 bits of param2.

Fixes: b4f8e52 ("rpmsg: Introduce Qualcomm RPM glink driver")
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20241007235935.6216-1-jonathan@marek.ca
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: flto

drivers/rpmsg/qcom_glink_native.c

@@ -1204,7 +1204,8 @@ void qcom_glink_native_rx(struct qcom_glink *glink)
 			ret = qcom_glink_rx_open_ack(glink, param1);
 			break;
 		case GLINK_CMD_OPEN:
-			ret = qcom_glink_rx_defer(glink, param2);
+			/* upper 16 bits of param2 are the "prio" field */
+			ret = qcom_glink_rx_defer(glink, param2 & 0xffff);
 			break;
 		case GLINK_CMD_TX_DATA:
 		case GLINK_CMD_TX_DATA_CONT: