new macros:
ONE_ADC_CHIP: reuse IO pins of 2nd ADC
NM64_PRIM: drive ADS8688 and LTC2656 on nm64_prim board
ADC40MHz: all clocks at half frequency.
EPIPE_DEPTH: reduce number of epfifos per channel.
ONE_CHANNEL: omit ADC B-channel pipe.
git-svn-id: svn+ssh://asterix.ieap.uni-kiel.de/home/subversion/stephan/solo/eda@7715 bc5caf13-1734-44f8-af43-603852e9ee25