[nrf toup][nrfconnect] Add Kconfig for ExternalFlashManager

Add `CONFIG_CHIP_EXTERNAL_FLASH_MANAGER` Kconfig that guards power
state handling for nRF QSPI NOR external flash.

Signed-off-by: Adrian Gielniewski <adrian.gielniewski@nordicsemi.no>

Author: adigie

config/nrfconnect/chip-module/Kconfig

@@ -529,4 +529,12 @@ config CHIP_CHIPOBLE_SINGLE_CONNECTION
 	  Limit support for chip-over-BLE (CHIPoBLE) to a single connection.
 	  When set, CHIPoBLE advertisements will stop while a CHIPoBLE connection is active.
 
+config CHIP_EXTERNAL_FLASH_MANAGER
+	bool "External flash manager support"
+	default y
+	depends on PM_DEVICE && NORDIC_QSPI_NOR
+	help
+	  Enables handling external flash power state transitions for operations
+	  that use the nRF QSPI NOR external flash.
+
 endif # CHIP

src/platform/nrfconnect/ExternalFlashManager.h

@@ -45,14 +45,16 @@ class ExternalFlashManager
 
     void DoAction(Action aAction)
     {
-#if defined(CONFIG_PM_DEVICE) && defined(CONFIG_NORDIC_QSPI_NOR)
+#if defined(CONFIG_CHIP_EXTERNAL_FLASH_MANAGER)
         // utilize the QSPI driver sleep power mode
         const auto * qspi_dev = DEVICE_DT_GET(DT_INST(0, nordic_qspi_nor));
         if (device_is_ready(qspi_dev))
         {
             const auto requestedAction = Action::WAKE_UP == aAction ? PM_DEVICE_ACTION_RESUME : PM_DEVICE_ACTION_SUSPEND;
             (void) pm_device_action_run(qspi_dev, requestedAction); // not much can be done in case of a failure
         }
+#else
+        (void) aAction;
 #endif
     }