deb-pkg: Add all Makefiles to header package

I discovered that make deb-pkg does not add Makefile_32.cpu from
arch/x86 directory when doing i386 kernel build and package build.
Fix it by greedily adding all Makefiles.

Reported-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl>
Signed-off-by: maximilian attems <max@stro.at>
Signed-off-by: Michal Marek <mmarek@suse.cz>