ARM: socfpga: Update socfpga_defconfig

Enable the following bits:

CONFIG_TOUCHSCREEN_STMPE
 - STMPE touchscreen support, needed on MCVEVK as it contains the
   chip. This also enables the STMPE MFD device and touchscreen
   input support.

CONFIG_USB_STORAGE
 - USB storage support is often used, so enable it.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>