tools build: Fix quiet cmd indentation

The tools quiet cmd output has mismatched indentation (and extra space
character between cmd name and target name) compared to the rest of
kbuild out:

  HOSTCC  scripts/insert-sys-cert
  LD       /srv/code/tools/objtool/arch/x86/objtool-in.o
  LD       /srv/code/tools/objtool/libsubcmd-in.o
  AR       /srv/code/tools/objtool/libsubcmd.a
  HOSTLD  scripts/genksyms/genksyms
  CC      scripts/mod/empty.o
  HOSTCC  scripts/mod/mk_elfconfig
  CC      scripts/mod/devicetable-offsets.s
  MKELF   scripts/mod/elfconfig.h
  HOSTCC  scripts/mod/modpost.o
  HOSTCC  scripts/mod/file2alias.o
  HOSTCC  scripts/mod/sumversion.o
  LD       /srv/code/tools/objtool/objtool-in.o
  LINK     /srv/code/tools/objtool/objtool
  HOSTLD  scripts/mod/modpost
  CC      kernel/bounds.s

Adjust to match the rest of kbuild.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>