mfd: tps65086: Read DEVICE ID register 1 from device

mfd: tps65086: Read DEVICE ID register 1 from device

This commit prepares a following commit for the regulator part of the MFD.
The driver should support different device chips that differ in their
register definitions, for instance to control LDOA1 and SWB2.
So it is necessary to use a dedicated regulator description for a
specific device variant. Thus, the content from DEVICEID Register 1 is
used to choose a dedicated configuration between the different device
variants.

Signed-off-by: Andre Werner <andre.werner@systec-electronic.com>
Link: https://lore.kernel.org/r/20230818083721.29790-2-andre.werner@systec-electronic.com
Signed-off-by: Lee Jones <lee@kernel.org>