drm/msm: Truncate the buffer object name if the copy from user failed

(Resend since there was a compile error that I forgot to commit before sending)

If there is a error while doing a copy_from_user() for MSM_INFO_SET_NAME
make sure to truncate the object name so that there isn't a chance that
we'll have random data in the string.

This is on top of [1] reported and fixed by Dan Carpenter.

[1] https://patchwork.freedesktop.org/series/56656/

Fixes: f05c83e7 ("drm/msm: add uapi to get/set debug name")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: NRob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_drv.c

@@ -852,8 +852,11 @@ static int msm_ioctl_gem_info(struct drm_device *dev, void *data,
 			break;
 		}
 		if (copy_from_user(msm_obj->name, u64_to_user_ptr(args->value),
-				   args->len))
+				   args->len)) {
+			msm_obj->name[0] = '\0';
 			ret = -EFAULT;
+			break;
+		}
 		msm_obj->name[args->len] = '\0';
 		for (i = 0; i < args->len; i++) {
 			if (!isprint(msm_obj->name[i])) {