Include autoconf.h into every kernel compilation via the gcc command line
using -imacros.  This ensures that we have the kernel configuration
included from the start, rather than relying on each file having #include
<linux/config.h> as appropriate.  History has shown that this is something
which is difficult to get right.

Since we now include the kernel configuration automatically, make
configcheck becomes meaningless, so remove it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>