rfnoc: Enabled SW flush mechanism impl'd in noc_shell

- UHD will now "disconnect" the noc_block data-path from
  the crossbar when the block's dtor is invoked. This allows
  long running or slow blocks to empty out rapidly during
  teardown.
- UHD will also attempt to flush at init time in case a block
  is destroyed abnormally. The goal of the flush mechanism is
  to not lock up the FPGA
- noc_shell compat number is now 3

1 files changed, 0 insertions, 0 deletions

diff --git a/fpga-src b/fpga-src
-Subproject 2e310fae0a6a7354c250fca36060daaeaac1535
+Subproject f27926410328883a315d5230146936d2d782bd0