f4pga/flows: fix usage of clock pads on eos-s3

Add --no-default-bitstream to qlfasm invocation, this fixes problem
with clock pads not working. This follows behaviour of f4pga-arch-defs
where --no-default-bitstream is always passed to qlfasm.

Signed-off-by: Artur Kowalski <artur.kowalski@3mdeb.com>

f4pga/flows/platforms.yml

@@ -512,6 +512,7 @@ ql-eos-s3:
         inputs:
           '#1': '${:fasm}'
           '#2': '${:eblif[noext]}.bit'
+          '#3': --no-default-bitstream
           dev-type: ql-eos-s3
       values:
         build_dir: .