openlane/user_module: remove unused value

- FP_CORE_UTIL: since FP_SIZING is absolute
- PL_RESIZER_BUFFER_OUTPUT_PORTS: see OpenLane#1434
- SYNTH_READ_BLACKBOX_LIB: seems to fails with gf180mcu

openlane/user_module/config.json

diff --git a/openlane/user_module/config.json b/openlane/user_module/config.json
index 6b67357..2efaed4 100644
--- a/openlane/user_module/config.json
+++ b/openlane/user_module/config.json
@@ -11,14 +11,11 @@
     "CLOCK_NET": "",
     "FP_SIZING": "absolute",
     "DIE_AREA": "0 0 250 250",
-    "FP_CORE_UTIL": 45,
     "PL_BASIC_PLACEMENT": 1,
     "PL_TARGET_DENSITY": 0.55,
     "VDD_NETS": ["vccd1"],
     "GND_NETS": ["vssd1"],
     "DIODE_INSERTION_STRATEGY": 4,
-    "PL_RESIZER_BUFFER_OUTPUT_PORTS": 0,
-    "SYNTH_READ_BLACKBOX_LIB": 1,
     "RUN_CVC": 1,
     "RUN_KLAYOUT_XOR": 0,
     "RUN_KLAYOUT_DRC": 0,