regmap: Updates for v4.17

This is a fairly large set of updates for regmap, mainly bugfixes.  The
biggest bit of this is some fixes for the bulk operations code which
had issues in some use cases, Charles Keepax has sorted them out.  We
also gained the ability to use debugfs with syscon regmaps and to
specify the clock to be used with MMIO regmaps.
Merge remote-tracking branches 'regmap/topic/debugfs' and 'regmap/topic/mmio-clk' into regmap-next