drivers: sensor: ti: ina230: Fix shared data between instances

This commit fixes a shared context between multiple instances of the
INA230 and INA236 driver. The issue is the naming of the instance data in
`INA230_DRIVER_INIT` macro when we have one instance of INA230 and one
of INA236 the name of the data variable will be `drv_data_0`. This
variable will then be passed to both instances.

Signed-off-by: Tomáš Juřena <jurenatomas@gmail.com>