microblaze: Fix problem with removing zero length files

Adding one new line was recommended solution.
Test with make distclean
Tested-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/include/asm/auxvec.h

+

arch/microblaze/include/asm/cputable.h

+

arch/microblaze/include/asm/hw_irq.h

+

arch/microblaze/include/asm/user.h

+

arch/microblaze/include/asm/vga.h

+