projects/ad7405_fmc:Update readme for ZED

I added an example configurations for ZED.

Signed-off-by: Capota Bianca <bianca-ramona.capota@analog.com>

Author: BCapota

projects/ad7405_fmc/zed/README.md

@@ -1,4 +1,4 @@
-<!-- no_build_example, no_dts, no_no_os -->
+<!-- no_dts, no_no_os -->
 
 # AD7405-FMC/ZED HDL
 
@@ -17,4 +17,14 @@ The overwritable parameter from the environment:
 
 - LVDS_CMOS_N - specific to the type of the data and clock signals
   - 0 - Single-ended data and clock signals (default)
-  - 1 - Differential data and clock signals
+  - 1 - Differential data and clock signals
+
+### Example configurations
+
+#### Configuration using CMOS interface (default)
+
+This specific command is equivalent to running "make" only:
+
+```
+make LVDS_CMOS_N=0
+```