include: remove trailing whitespaces

include/debug.mk

include/depends.mk

include/host.mk

include/kernel.mk

include/netfilter.mk

include/package-bin.mk

include/package-defaults.mk

include/package-dumpinfo.mk

include/package.mk

include/prereq-build.mk

include/prereq.mk

include/quilt.mk

include/shell.sh

include/subdir.mk

include/toolchain-build.mk

include/toplevel.mk

include/unpack.mk

include/verbose.mk