FPGA: Cyclon II: Correctly reset the FPGA before configuration

FPGA: Cyclon II: Correctly reset the FPGA before configuration

Deassert the CONFIG pin before asserting it again. This assures that the
FPGA will be resetted and therefore configuration will be correctly
enabled.

This is also already done on other FPGA's, e.g. Stratix.

Signed-off-by: Stephan Gatzka <stephan.gatzka@hbm.com>
Signed-off-by: Stefan Roese <sr@denx.de>