projects/ad7134_fmc: Update AD7134 SPIE project. Add FMC pinout. Test software support

[laurent-19]

This PR covers the AD7134 SPI Engine project checking and updates. Changes and additions include:

• Added txt description of all FMC pins used/unused
• Updated constraint files with FMC pinout location

Hardware test with available software:
AD7134 NO-OS needs updating for new HDL design (PWM trigger for SPIE offload)
NO-OS PR not yet up, waiting for CN0561 PR to see what soft team expects.

Test failed. Initialization of ADC device fails. Debug log:

• ad713x_init failed due to CHIP_TYPE == 0, it should be CHIP_TYPE == 7
• first ad713x device (ADC chs 0-3) CHIP_TYPE not initialized
• second ad713x device (ADC chs 3-7) initialized successfully

Force initialization via the Vitis debugger ==> 0V on ADC channels, conversation fails

PR Type

• Bug fix (change that fixes an issue)
• New feature (change that adds new functionality)
• Breaking change (has dependencies in other repos or will cause CI to fail)

PR Checklist

• I have followed the code style guidelines
• I have performed a self-review of changes
• I have compiled all hdl projects and libraries affected by this PR
• I have tested in hardware affected projects, at least on relevant boards
• I have commented my code, at least hard-to-understand parts
• I have signed off all commits from this PR
• I have updated the documentation (wiki pages, ReadMe files, Copyright etc)
• I have not introduced new Warnings/Critical Warnings on compilation
• I have added new hdl testbenches or updated existing ones

[PopPaul2021]

Looks good to me!