library/util_axis_fifo_asym: fix internal fifo (#1907)

The internal i_fifo is relying on the default value
for the REMOVE_NULL_BEAT_EN, which is disabled. Signals
full, empty, almost full, almost empty will only work
when this parameter is disabled.
Otherwise, it would be necessary to define a new policy
to define how that is presented to the user.
This commit forces REMOVE_NULL_BEAT_EN to be disabled in
its i_fifo instance.

Signed-off-by: Carlos Souza <carlos.souza@analog.com>

Author: caosjr

library/util_axis_fifo_asym/util_axis_fifo_asym.v

@@ -117,7 +117,8 @@ module util_axis_fifo_asym #(
         .ALMOST_EMPTY_THRESHOLD (A_ALMOST_EMPTY_THRESHOLD),
         .ALMOST_FULL_THRESHOLD (A_ALMOST_FULL_THRESHOLD),
         .TKEEP_EN (TKEEP_EN),
-        .TLAST_EN (TLAST_EN)
+        .TLAST_EN (TLAST_EN),
+        .REMOVE_NULL_BEAT_EN(0)
       ) i_fifo (
         .m_axis_aclk    (m_axis_aclk),
         .m_axis_aresetn (m_axis_aresetn),