mfd: Save device node parsed platform data for tps65910 sub devices

Save the allocated memory to store the parsed device node information
to the global device structure so that sub devices can directly use this
pointer.
In this way, the sub devices does not require to re-allocate the
memory for storing the sub-devices specific device node information.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>