Set number of cores using RISCY config instead of manual define

This was leading to -D NUM_CORES=2 -D NUM_CORES=1 in the command.
The NUM_CORES=2 seems to have been winning, but this is obviously
far from ideal.

src_SSITH_P3/Makefile

@@ -33,7 +33,6 @@ BSC_COMPILATION_FLAGS += \
 	-D PERFORMANCE_MONITORING \
 	-D SHIFT_BARREL    \
 	-D MULT_SERIAL    \
-        -D NUM_CORES=2 \
 	-D Near_Mem_Caches    \
 	-D FABRIC64    \
 	-D CAP128 \
@@ -49,6 +48,9 @@ SYNTH_BSC_OPTIONS = -D XILINX_XCVU9P
 # Sim only BSC_COMPILATION_FLAGS
 SIM_BSC_OPTIONS = -D BSIM
 
+# Set number of cores for RISCY config
+CORE_NUM = 2
+
 # Only used if we don't have INCLUDE_GDB_CONTROL
 #	-D EXTERNAL_DEBUG_MODULE