mimxrt/sdcard: Fix deadlock in sdcard_power_off when no card present.

The sdcard_power_off function was unconditionally sending GO_IDLE_STATE
command even when the card was never successfully initialized or not
present. This caused a deadlock in USDHC_WaitCommandDone which has an
infinite loop waiting for command completion.

The fix checks card->state->initialized before attempting to send the
command, preventing communication with non-existent hardware.

Signed-off-by: Andrew Leech <[email protected]>

Author: pi-anl

ports/mimxrt/sdcard.c

@@ -986,7 +986,11 @@ bool sdcard_power_on(mimxrt_sdcard_obj_t *card) {
 }
 
 bool sdcard_power_off(mimxrt_sdcard_obj_t *card) {
-    (void)sdcard_cmd_go_idle_state(card);
+    // Only send GO_IDLE_STATE command if card was successfully initialized
+    // Sending commands to a non-existent card will deadlock waiting for response
+    if (card->state->initialized) {
+        (void)sdcard_cmd_go_idle_state(card);
+    }
 
     // Reset card bus clock
     USDHC_SetDataBusWidth(card->usdhc_inst, kUSDHC_DataBusWidth1Bit);