correct adafruit flash size for itsybitsy and qt rp2040 (#348)

from 4 MB to 8 MB

Author: hathach

src/boards/include/boards/adafruit_itsybitsy_rp2040.h

@@ -80,7 +80,7 @@
 #endif
 
 #ifndef PICO_FLASH_SIZE_BYTES
-#define PICO_FLASH_SIZE_BYTES (4 * 1024 * 1024)
+#define PICO_FLASH_SIZE_BYTES (8 * 1024 * 1024)
 #endif
 
 // All boards have B1 RP2040

src/boards/include/boards/adafruit_qtpy_rp2040.h

@@ -79,7 +79,7 @@
 #endif
 
 #ifndef PICO_FLASH_SIZE_BYTES
-#define PICO_FLASH_SIZE_BYTES (4 * 1024 * 1024)
+#define PICO_FLASH_SIZE_BYTES (8 * 1024 * 1024)
 #endif
 
 // All boards have B1 RP2040