build: clean up building kernel modules using meson

The meson.build files for building the kernel modules directory could
be improved now that it is extracted from the EAL. For example, no
global processing is necessary inside the kernel folder, just need to
subdir to the appropriate bsd or linux folder to do the actual work.

To avoid potential race conditions with the BSD module builds when
the kernel build system is creating the dev_if.h and other files,
we serialize the kernel module builds (all 2 of them!) by setting
up each module to depend on all the previous.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>