raspberrypi/boards: add DEFAULT_SD_* for Metro RP2040 and Feather RP2040 Adalogger

Both boards have onboard microSD slots but were missing the
DEFAULT_SD_* pin defines that enable CircuitPython's native SD
automount. Without these, SD-over-USB-MSC only worked via user boot.py
code and hit the heap-mount race in get_vfs().

Pin wiring verified on hardware against the board schematics; CD pin
polarity (DEFAULT_SD_CARD_INSERTED=true) confirmed by runtime test.

Companion to #10963 (automount at filesystem init) and #NNNN (per-LUN
PREVENT_ALLOW response). Fixes the last mile for #10965.

Author: mikeysklar

ports/raspberrypi/boards/adafruit_feather_rp2040_adalogger/mpconfigboard.h

@@ -23,3 +23,11 @@
 
 // #define CIRCUITPY_CONSOLE_UART_RX DEFAULT_UART_BUS_RX
 // #define CIRCUITPY_CONSOLE_UART_TX DEFAULT_UART_BUS_TX
+
+// Onboard microSD slot on SPI1.
+#define DEFAULT_SD_SCK (&pin_GPIO18)
+#define DEFAULT_SD_MOSI (&pin_GPIO19)
+#define DEFAULT_SD_MISO (&pin_GPIO20)
+#define DEFAULT_SD_CS (&pin_GPIO23)
+#define DEFAULT_SD_CARD_DETECT (&pin_GPIO16)
+#define DEFAULT_SD_CARD_INSERTED true

ports/raspberrypi/boards/adafruit_metro_rp2040/mpconfigboard.h

@@ -20,3 +20,11 @@
 
 #define DEFAULT_UART_BUS_RX (&pin_GPIO1)
 #define DEFAULT_UART_BUS_TX (&pin_GPIO0)
+
+// Onboard microSD slot.
+#define DEFAULT_SD_SCK (&pin_GPIO18)
+#define DEFAULT_SD_MOSI (&pin_GPIO19)
+#define DEFAULT_SD_MISO (&pin_GPIO20)
+#define DEFAULT_SD_CS (&pin_GPIO23)
+#define DEFAULT_SD_CARD_DETECT (&pin_GPIO15)
+#define DEFAULT_SD_CARD_INSERTED true