externalsrc/devtool: Fix to work with fixed export funcition flags handling

externalsrc/devtool: Fix to work with fixed export funcition flags handling

If we fix bitbake to correctly handle the cleandirs and fakeroot flags
for tasks handled by EXPORT_FUNCTIONS, we break devtool since it only
considers these for top level functions. Add in extra code to intercept
the cleandirs flags for commonly used sub functions too.

[YOCTO #8621]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 67fad829f37ed0a8e20c599d2b65635158591d06)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>