ARM: mini2440_defconfig: Bring back lost (but wanted) options

The config was not updated for some time so it needs updates to get the
same options as wanted initially:
 - SERIAL_DEV_BUS is now needed for BT_HCIUART_LL;
 - USB_GADGET_S3C2410 was replaced by USB_S3C2410;
 - S3C24XX_DMAC is now needed for MMC_S3C;

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>