build: package-ipkg: avoid calling wildcard twice

build: package-ipkg: avoid calling wildcard twice

Instead of calling $(wildcard) to check if the removal list is empty,
then calling it again to actually remove the files, define a function so
that the arguments are expanded only once when it gets called.

Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>
(cherry picked from commit 40acc13ca72ca7d2815dc5d94549d5dc48e16e98)