pm: Move pm_initialize call from driver_initialize to xxx_pminitialize

since it's too late with the below commit:
ommit a594a5d7a8
Author: chao.an <anchao@xiaomi.com>
Date:   Mon Apr 11 19:44:26 2022 +0800

    sched/init: drivers_initialize() should be late than up_initialize()

    up_initialize
    |
     ->up_serialinit
       |
        ->uart_register  /* ("/dev/console", &CONSOLE_DEV); */

    drivers_initialize
    |
     ->syslog_console_init
       |
        ->register_driver /* ("/dev/console", &g_consoleops, 0666, NULL); */

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

drivers/drivers_initialize.c

@@ -54,12 +54,6 @@
 
 void drivers_initialize(void)
 {
-#ifdef CONFIG_PM
-  /* Initialize power management subsystem proper */
-
-  pm_initialize();
-#endif
-
   /* Register devices */
 
   syslog_initialize();