USB: ehci-msm: Make of_device_id array const

Make of_device_id array const, because all OF functions handle
it as const.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ehci-msm.c b/drivers/usb/host/ehci-msm.c
index 982c09b..934b39d 100644
--- a/drivers/usb/host/ehci-msm.c
+++ b/drivers/usb/host/ehci-msm.c
@@ -190,7 +190,7 @@
 	.resume          = ehci_msm_pm_resume,
 };
 
-static struct of_device_id msm_ehci_dt_match[] = {
+static const struct of_device_id msm_ehci_dt_match[] = {
 	{ .compatible = "qcom,ehci-host", },
 	{}
 };