Previously the FPGA was configured externally on the Achilles. On newer versions
this is changed and barebox has to configure the FPGA before the SDRAM can be
used.

If the FPGA is configured via JTAG or from an external memory, the *-bringup
version can be used.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>