examples: fix flattening directory layout on install

examples: fix flattening directory layout on install

By installing the examples one-by-one in a loop in the examples
meson.build file we effectively flattened out the structure of the examples
folder and omitted some common and shared subfolders that were never
directly built.  Instead, we can remove the loop and just have the whole
"examples" folder installed as-is in a single statement, preserving its
directory structure, and thereby fixing the build of a number of the
examples.

Fixes: 2daf565f91b5 ("examples: install as part of ninja install")
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>