kconfig: autogenerated config_is_xxx macro

this will allow to use to use

	if(config_is_xxx())
	if(config_is_xxx_module())

in the code instead of

	#ifdef CONFIG_xxx
	#ifdef CONFIG_xxx_MODULE

and now let the compiler remove the non usefull code and not the
pre-processor

as done in the mach-types for arm as exmaple

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>