ACPI: driver: Drop driver_data pointer clearing from two drivers

It is not necessary to clear the driver_data pointer in the ACPI
companion device object on driver remove in the EC and SMBUS HC
ACPI drivers because that pointer is not used there any more after
recent changes.

Drop the unnecessary statements.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/6242843.lOV4Wx5bFT@rafael.j.wysocki