Fix required headers for cuda/hip platforms

src/pystencils/backend/platforms/cuda.py

@@ -8,4 +8,6 @@ class CudaPlatform(GenericGpu):
 
     @property
     def required_headers(self) -> set[str]:
-        return set()
+        return {
+            '"gpu_atomics.h"',
+        }

src/pystencils/backend/platforms/hip.py

@@ -8,4 +8,7 @@ class HipPlatform(GenericGpu):
 
     @property
     def required_headers(self) -> set[str]:
-        return {'"pystencils_runtime/hip.h"'}
+        return {
+            '"gpu_atomics.h"',
+            '"pystencils_runtime/hip.h"',
+        }