gpio: fix missing cmakelists for esp32s2beta

components/soc/esp32s2beta/sources.cmake

@@ -1,6 +1,8 @@
 set(SOC_SRCS    "cpu_util.c"
+                "gpio_periph.c"
                 "rtc_clk.c"
                 "rtc_init.c"
+                "rtc_periph.c"
                 "rtc_pm.c"
                 "rtc_sleep.c"
                 "rtc_time.c"