GPU: correct detection of Apple M1 GPU

Don't cheat

src/detection/gpu/gpu.h

@@ -6,6 +6,7 @@
 #include "fastfetch.h"
 
 #define FF_GPU_TEMP_UNSET (0/0.0)
+#define FF_GPU_CORE_COUNT_UNSET -1
 
 typedef struct FFGPUResult
 {
@@ -13,6 +14,7 @@ typedef struct FFGPUResult
     FFstrbuf name;
     FFstrbuf driver;
     double temperature;
+    int coreCount;
 } FFGPUResult;
 
 const FFlist* ffDetectGPU(const FFinstance* instance);