intel: remove extra \n from warning string

(cherry picked from commit 42e9bde0fa)

src/mesa/drivers/dri/intel/intel_screen.c

@@ -236,7 +236,7 @@ intel_get_param(__DRIscreenPrivate *psp, int param, int *value)
 
    ret = drmCommandWriteRead(psp->fd, DRM_I915_GETPARAM, &gp, sizeof(gp));
    if (ret) {
-      _mesa_warning(NULL, "drm_i915_getparam: %d\n", ret);
+      _mesa_warning(NULL, "drm_i915_getparam: %d", ret);
       return GL_FALSE;
    }