ASoC: wcd9xxx: fix the NULL pointer dereference causing the crash

If the probe of the device is unsuccessful then the wcd9xxx
structure is unallocated but is not initialized to NULL.
If some operation like reset comes, it would dereference the wcd9xxx
structure leading to the target crash.
Fix by intializing the client data to NULL after it is unallocated.

Signed-off-by: Aviral Gupta <aviralg@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
mfd: wcd9xxx: Add support for REPEAT_CHANGE_VALUE

Slimbus supports ability to write upto 16 bytes to the same register as
one transaction on the bus through REPEAT_CHANGE_VALUE slimbus message.
Add support to write codec register with multiple values using
REPEAT_CHANGE_VALUE. Not all sizes from 1 to 16 are supported by such a
message, add support in driver to be able to write all sizes from 1 to
16 by splitting the register writes of unsupported sizes into multiple
writes of supported sizes.

Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>