refactor(etm): move ETM retention info from HAL to driver layer

Move soc_etm_retention_desc_t type definition and soc_etm_retention_info
data from hal component to esp_hw_support component, following the
pattern of other peripheral retention data (e.g. MWDT).

- Create esp_private/etm_retention.h with type and extern declaration
- Create port/<target>/etm_retention.c for each target with retention data
- Remove hal/<target>/etm_periph.c and hal/include/hal/etm_periph.h
- Update esp_etm.c to include the new header
- Update CMakeLists.txt in both components

components/esp_hw_support/include/esp_private/etm_retention.h

@@ -0,0 +1,37 @@
+/*
+ * SPDX-FileCopyrightText: 2023-2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include "soc/soc_caps.h"
+#include "soc/regdma.h"
+#if SOC_HAS(ETM)
+#include "hal/etm_ll.h"
+#endif
+#if SOC_HAS(PAU)
+#include "soc/retention_periph_defs.h"
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if SOC_HAS(PAU)
+
+typedef struct {
+    periph_retention_module_t module;                  // ID of the ETM as a retention module
+    const regdma_entries_config_t *regdma_entry_array; // Array of regdma entries for retention
+    uint32_t array_size;                               // Size of the regdma_entry_array
+} soc_etm_retention_desc_t;
+
+extern const soc_etm_retention_desc_t soc_etm_retention_info[ETM_LL_GET(INST_NUM)];
+
+#endif // SOC_HAS(PAU)
+
+#ifdef __cplusplus
+}
+#endif