x86, boot: add new generated files to the appropriate .gitignore files
git status complains of untracked (generated) files in arch/x86/boot..
# Untracked files:
# (use "git add <file>..." to include in what will be committed)
#
# ../../arch/x86/boot/compressed/mkpiggy
# ../../arch/x86/boot/compressed/piggy.S
# ../../arch/x86/boot/compressed/vmlinux.lds
# ../../arch/x86/boot/voffset.h
# ../../arch/x86/boot/zoffset.h
..so adjust .gitignore files accordingly.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>