shared/tinyusb: Revert setting of CFG_TUD_CDC_EP_BUFSIZE to 256.

This reverts commit 0613d3e3.

The value of CFG_TUD_CDC_EP_BUFSIZE should match the endpoint size,
otherwise data may stay in the lower layers of the USB stack (and not
passed up to the higher layers) until a total of CFG_TUD_CDC_EP_BUFSIZE
bytes have been received, which may not happen for a long time.

Fixes issue #11253.
Signed-off-by: Damien George <damien@micropython.org>

shared/tinyusb/tusb_config.h

@@ -59,7 +59,6 @@
 
 // CDC Configuration
 #if CFG_TUD_CDC
-#define CFG_TUD_CDC_EP_BUFSIZE  (256)
 #define CFG_TUD_CDC_RX_BUFSIZE  (256)
 #define CFG_TUD_CDC_TX_BUFSIZE  (256)
 #endif