make: use DIST_SUBDIRS

make: use DIST_SUBDIRS

As per automake manual[1], DIST_SUBDIRS should be used to recurse into
the subdirectories those we want to ship as part of make dist and use
SUBDIRS for conditionally building the directories. Adopt this rule
across the source.

[1] https://www.gnu.org/software/automake/manual/html_node/SUBDIRS-vs-DIST_005fSUBDIRS.html

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
(cherry picked from commit 48d49fbbe3eaf9c1ddd640f99cd8921752ab4e1d)