The 'filechk' in the latest Linux works more simply, reliably.

- Do not show CHK every time
- Delete the *.tmp file when the filechk_$(1) fails
- Do not open the first prerequisite. This is unneeded in most cases.

I deleted pointeless dependency on Makefile.

Also delete the meaningless assignment to 'targets' because filechk
does not generate .cmd file.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>