staging: ccree: Convert to platform_{get,set}_drvdata()

Platform devices are expected to use wrapper functions,
platform_{get,set}_drvdata() with platform_device as argument,
for getting and setting the driver data. dev_{get,set}_drvdata()
are using &plat_dev->dev.
For wrapper functions we can directly pass a struct platform_device.

dev_set_drvdata() is redundant and therefore removed. The driver core
clears the driver data to NULL after device_release or on probe failure.

Signed-off-by: Suniel Mahesh <sunil.m@techveda.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>