Since the blob files are generated a different way
in compare with plain compiling we use for regular
*.c files -- add own Makefile.pie for this target.

This increases readability of general Makefile
and Makefile.pie itself.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>