staging: ccree: use a consistent file naming convention

The ccree driver source files were using an inconsistent
naming convention stemming from what the company was called
when they were added.

Move to a single consistent naming convention for better
code readability.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>