Update hellbender_0001.h (#2359)

Replace the incorrect `#define PICO_RP2350B 1` with the correct `#define PICO_RP2350A 0`

Fixes #2286

Author: lurch

src/boards/include/boards/hellbender_0001.h

@@ -138,7 +138,7 @@
 #define HELLBENDER_0001_BLACKBOX_FLASH_SIZE_BYTES (16 * 1024 * 1024)
 
 // --- RP2350 VARIANT ---
-#define PICO_RP2350B 1
+#define PICO_RP2350A 0
 
 // pico_cmake_set_default PICO_RP2350_A2_SUPPORTED = 1
 #ifndef PICO_RP2350_A2_SUPPORTED