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>