projects/riscv_doom: Don't fail on timing by default

Just to avoid questions from people not doing seed exploration ...

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>

projects/riscv_doom/Makefile

@@ -30,6 +30,7 @@ SEED ?= 4
 
 YOSYS_SYNTH_ARGS = -dffe_min_ce_use 4 -abc9 -device u -dsp
 NEXTPNR_ARGS = --pre-pack data/clocks.py --pre-place $(CORE_no2ice40_DIR)/sw/serdes-nextpnr-place.py --seed $(SEED)
+NEXTPNR_ARGS += --timing-allow-fail
 
 # Include default rules
 include ../../build/project-rules.mk