[cmake] if CCACHE is set but not found, make it fatal (#2885)

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2885
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Co-authored-by: DraVee <caiooliveirafarias0@gmail.com>
Co-committed-by: DraVee <caiooliveirafarias0@gmail.com>

CMakeLists.txt

@@ -231,7 +231,7 @@ if(USE_CCACHE)
         set(CMAKE_C_COMPILER_LAUNCHER ${CCACHE_BINARY})
         set(CMAKE_CXX_COMPILER_LAUNCHER ${CCACHE_BINARY})
     else()
-        message(WARNING "USE_CCACHE enabled, but no executable found at: ${CCACHE_PATH}")
+        message(FATAL_ERROR "USE_CCACHE enabled, but no executable found at: ${CCACHE_PATH}")
     endif()
 endif()