staging: ccree: remove ccree staging driver copy

The ccree driver is now in the cryptodev tree, so remove it from
drivers/staging as it's no longer needed here.

Based on a patch from Gilad, but the mailing list didn't like it :(

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