docs: AD7616/ad7606 documentation update

Remove reference to the axi_ad7616 interrupt as it does not exist in the HDL
design.
Update the legends for ad7606/ad7616 docs.

Signed-off-by: Pop Ioan Daniel <[email protected]>

Author: PIoandan

docs/projects/ad7606x_fmc/index.rst

@@ -289,7 +289,6 @@ spi_ad7606 **   12  56         88
 .. admonition:: Legend
    :class: note
 
-   - ``*`` instantiated only for INTF=0 (parallel interface)
    - ``**`` instantiated only for INTF=1 (serial interface)
 
 Building the HDL project

docs/projects/ad7616_sdz/index.rst

@@ -239,13 +239,11 @@ Instance name   HDL Linux Zynq Actual Zynq
 =============== === ========== ===========
 axi_ad7616_dma  13  57         89
 spi_ad7616 **   12  56         88
-axi_ad7616 *    10  54         87
 =============== === ========== ===========
 
 .. admonition:: Legend
    :class: note
 
-   - ``*`` instantiated only for INTF=0 (parallel interface)
    - ``**`` instantiated only for INTF=1 (serial interface)
 
 Building the HDL project