ARM: dts: socfpga: Enable QSPI on the Cyclone5 sockit

Enable the QSPI node and add the flash chip.

Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
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v3: Use n25q00 for the compatible entry for the flash part and
    tested on SoCKit
v2: Remove partition entries for the SoCKIT