regmap: cache: Fix regcache_sync_block for non-autoincrementing devices

Commit 75a5f89f635c ("regmap: cache: Write consecutive registers in a single
block write") expected that autoincrementing writes are supported if
hardware has a register format which can support raw writes.

This is not necessarily true and thus for instance rbtree sync can fail when
there is need to sync multiple consecutive registers but block write to
device fails due not supported autoincrementing writes.

Fix this by spliting raw block sync to series of single register writes for
devices that don't support autoincrementing writes.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
---
I noticed this with Realtek RT5642 audio codec which didn't resume properly
since first block write having more data than for single register failed to
not acknowledged I2C write during regcache_sync(). Chip acknowledges device
address, register address and two data bytes for its word size registers but
next data byte is not which then causes aborted I2C transfer and aborted
register sync.
ASoC: rt5640: Do not allow regmap to use bulk read-write operations

Debugging showed Realtek RT5642 doesn't support autoincrementing writes so
driver should set the use_single_rw flag for regmap.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: Bard Liao <bardliao@realtek.com>
Cc: Oder Chiou <oder_chiou@realtek.com>
---
I'm not sure is this specific only to RT5642? I was thinking that because
commit 4c9185be5e8e ("ASoC: rt5640: Move cache sync() to resume()") is way
after 75a5f89f635c ("regmap: cache: Write consecutive registers in a single
block write") which started to use block writes during rbtree sync.
Or maybe 4c9185be5e8e was done on top of older kernel?