btrfs: do not directly include rwlock_types.h

There is already an error inside that header:

 #if !defined(__LINUX_SPINLOCK_TYPES_H)
 # error "Do not include directly, include spinlock_types.h"
 #endif

Thankfully it never get triggered as some other headers have already
included spinlock_types.h.

However clangd would still do a proper warning on that if only
extent_map.h is opened.
Fix it by using spinlock_types.h instead.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_map.h

@@ -4,7 +4,7 @@
 #define BTRFS_EXTENT_MAP_H
 
 #include <linux/compiler_types.h>
-#include <linux/rwlock_types.h>
+#include <linux/spinlock_types.h>
 #include <linux/rbtree.h>
 #include <linux/list.h>
 #include <linux/refcount.h>