Loop back the unused GPIO pins, and add all the SPI interface to system
wrapper instance.
The following system_top modules were changed:
- ad738x_fmc
- ad7616_sdz
- ad77681evb
- ad77681evb
- ad7768evb
- ad9739a_fmc
- ad9434
- adrv9739
- fmcadc5
- ad6676evb
- ad9265
- ad5766
- fmcomms5
- m2k