xfs: give rmap btree cursor error tracepoints their own class

xfs: give rmap btree cursor error tracepoints their own class

Source kernel commit: 71f5a17e526775f001f643c9d54e5b59fa29d7ac

Create a new tracepoint class for btree-related errors, then convert all
the rmap tracepoints to use it.  Also fix the one tracepoint that was
abusing the old class by making it a separate tracepoint.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>