docs/axi_ad9144: Delete oboselete IP doc

Signed-off-by: Stanca Pop <stanca.pop@analog.com>

Author: StancaPop

docs/library/axi_ad9144/index.rst

@@ -106,7 +106,6 @@ Obsolete IPs
 .. toctree::
    :maxdepth: 1
 
-   axi_ad9144/index
    axi_ad9371/index
    axi_ad9643/index
    axi_ad9671/index