esp32/machine_sdcard: Fix SDMMC slot assignment for non-default slots.

The SDMMC_HOST_DEFAULT() macro sets slot to SDMMC_HOST_SLOT_1, but this
was not being overridden when the user specified a different slot number.
This caused SDMMC initialization to fail on chips like ESP32-P4 when
trying to use slot 0.

This commit ensures the slot number passed to the SDCard constructor is
properly assigned to the host configuration structure.

Tested on ESP32-P4 with SD card on slot 0.

Signed-off-by: jetpax <jep@alphabetiq.com>

ports/esp32/machine_sdcard.c

@@ -166,6 +166,8 @@ static esp_err_t sdcard_ensure_card_init(sdcard_card_obj_t *self, bool force) {
 
         esp_err_t err = sdmmc_card_init(&(self->host), &(self->card));
         if (err == ESP_OK) {
+            // Ensure card's host structure has the correct slot after init
+            self->card.host.slot = self->host.slot;
             self->flags |= SDCARD_CARD_FLAGS_CARD_INIT_DONE;
         } else {
             self->flags &= ~SDCARD_CARD_FLAGS_CARD_INIT_DONE;
@@ -307,6 +309,7 @@ static mp_obj_t machine_sdcard_make_new(const mp_obj_type_t *type, size_t n_args
     else {
         sdmmc_host_t _temp_host = SDMMC_HOST_DEFAULT();
         _temp_host.max_freq_khz = freq / 1000;
+        _temp_host.slot = slot_num;
         self->host = _temp_host;
     }
     #endif