drivers: add headers install helper

drivers: add headers install helper

A lot of drivers export headers, reproduce the same facility than for
libraries.

Note: this change fixes an issue with the crypto scheduler headers which
were not installed properly. A separate backport will be sent to stable
branches.

Suggested-by: Bruce Richardson <bruce.richardson@intel.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>