i3c: dw: Save timing registers and other values

Add variables to store timing registers and other values.
These variables would be later used to restore registers
during resume without recomputation.

Signed-off-by: Aniket <aniketmaurya@google.com>
Link: https://lore.kernel.org/r/20240708062103.3296587-2-aniketmaurya@google.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>