common/qat: build drivers from common folder

common/qat: build drivers from common folder

Since the drivers in the common directory can be processed out of order, in
this case following the "bus" directory, we can simplify somewhat the build
of the QAT driver to be done entirely from the "common/qat" folder rather
than having it's build distributed across 3 folders.

This also opens up the possibility of building the QAT driver with crypto
only and the compression part disabled. It further allows more sensible
naming of the resulting shared library in case of standardizing library
names based on device class; i.e. common_qat is more descriptive for a
combined crypto/compression driver than either of the other two prefixes
individually.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>