fmcomms2: Cosmetic changes on *_bd.tcl script
fmcomms2: Cosmetic changes

Get rid of unwanted whitespaces.
fmcomms2: Use ad_iobuf instance on system_top

Use ad_iobuf instance on system top, instead of separate IOBUF instances.
fmcomms2: Add an additional SPI interface for up/down converter board

Supported carriers are: ZC706, ZC702 and Zed.