net: stmmac: dwmac-qcom-ethqos: add missing include

device_get_phy_mode() is declared in linux/property.h but this header
is not included.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c

@@ -6,6 +6,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/phy.h>
+#include <linux/property.h>
 #include "stmmac.h"
 #include "stmmac_platform.h"