kbuild,scripts: use non-builtin echo for '-e'

Alek reported that on Ubuntu, where dash is used, 'echo -e'
can't work, so let's use non-builtin echo in this case.

Reported-by: Alek Du <alek.du@intel.com>
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>