fix: update build instructions

Author: linsyking

core/Readme.md

@@ -9,14 +9,7 @@
 If you are using normal kernel, inside this directory, run:
 
 ```
-cmake -S . -B build -GNinja -DEPASS_LIBBPF=OFF
-make
-```
-
-If you are running our custom kernel with custom libbpf, compile with:
-
-```
-cmake -S . -B build -GNinja -DEPASS_LIBBPF=ON
+cmake -S . -B build -GNinja
 make
 ```