bootloader: fix section placement issues found by the check script

Summary of changes:

- bootloader_clock split into *_clock_init and *_clock_loader.
  Only esp_clk_apb_freq is in *_clock_loader.
- bootloader_common moved out of loader; functions needed in loader
  (or, referenced from bootloader_utility) were moved into
  bootloader_common_loader.c.
- assert and abort moved into bootloader_panic, made part of the
  loader
- rtc_clk and rtc_time made part of loader

components/bootloader_support/src/bootloader_panic.c

@@ -0,0 +1,38 @@
+// 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 "esp_log.h"
+#include "bootloader_common.h"
+#include "soc/cpu.h"
+#include "esp_rom_sys.h"
+
+
+void __assert_func(const char *file, int line, const char *func, const char *expr)
+{
+    esp_rom_printf("Assert failed in %s, %s:%d (%s)\r\n", func, file, line, expr);
+    while (1) {
+    }
+}
+
+void abort(void)
+{
+#if !CONFIG_ESP_SYSTEM_PANIC_SILENT_REBOOT
+    esp_rom_printf("abort() was called at PC 0x%08x\r\n", (intptr_t)__builtin_return_address(0) - 3);
+#endif
+    if (esp_cpu_in_ocd_debug_mode()) {
+        __asm__("break 0,0");
+    }
+    while (1) {
+    }
+}