soc: Add initial ESP32-C3 support

From internal commit 7761d6e8

components/soc/esp32c3/timer_periph.c

@@ -0,0 +1,28 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "soc/timer_periph.h"
+
+const timer_group_signal_conn_t timer_group_periph_signals = {
+    .groups = {
+        [0] = {
+            .module = PERIPH_TIMG0_MODULE,
+            .t0_irq_id = ETS_TG0_T0_LEVEL_INTR_SOURCE
+        },
+        [1] = {
+            .module = PERIPH_TIMG1_MODULE,
+            .t0_irq_id = ETS_TG1_T0_LEVEL_INTR_SOURCE,
+        }
+    }
+};