Fix assumption that pointers fits in a 'long'

Windows uses LLP64 model so [u]intptr_t is more correct.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/hash.h b/hash.h
index 0c3cdda..4b8c6bf 100644
--- a/hash.h
+++ b/hash.h
@@ -58,7 +58,7 @@
 	
 static inline unsigned long hash_ptr(void *ptr, unsigned int bits)
 {
-	return hash_long((unsigned long)ptr, bits);
+	return hash_long((uintptr_t)ptr, bits);
 }
 
 /*