Fix nexus kelvin_hw_sim build dependency

Change-Id: I3764a73372095463f801e88373bd7717748b01c0

platforms/nexus/kelvin.mk

diff --git a/platforms/nexus/kelvin.mk b/platforms/nexus/kelvin.mk
index 7cd60d1..e27e504 100644
--- a/platforms/nexus/kelvin.mk
+++ b/platforms/nexus/kelvin.mk
@@ -74,7 +74,7 @@
 		cp -rf bazel-bin/hdl/chisel/kelvin.v "$(KELVIN_HW_BAZEL_OUT_DIR)"
 
 ## Verilated Kelvin HW simulator
-kelvin_hw_sim: | $(KELVIN_HW_OUT_DIR)
+kelvin_hw_sim: | $(KELVIN_HW_BAZEL_OUT_DIR)
 	cd "$(KELVIN_HW_SRC_DIR)" && \
 		bazel build //tests/verilator_sim:core_sim && \
 		cp -rf bazel-bin/tests/verilator_sim/core_sim "$(KELVIN_HW_BAZEL_OUT_DIR)"