dts: add sqn to vendor-prefixes.txt

This is needed since commit f66b731
("drivers: hwspinlock: implement sqn hwspinlock driver") started
using it. Not sure how this got past CI.

Signed-off-by: Martí Bolívar <[email protected]>

Author: mbolivar-ampere

dts/bindings/vendor-prefixes.txt

@@ -581,6 +581,7 @@ sony	Sony Corporation
 spansion	Spansion Inc.
 sparkfun	SparkFun Electronics
 sprd	Spreadtrum Communications Inc.
+sqn	Sequans Communications
 sst	Silicon Storage Technology, Inc.
 sstar	Xiamen Xingchen(SigmaStar) Technology Co., Ltd. (formerly part of MStar Semiconductor, Inc.)
 st	STMicroelectronics