init.h: document the existence of __initconst

 * extern int initialize_foobar_device(int, int, int) __init;

 *

 * For initialized data:

 * You should insert __initdata between the variable name and equal

 * sign followed by value, e.g.:

 * You should insert __initdata or __initconst between the variable name

 * and equal sign followed by value, e.g.:

 *

 * static int init_variable __initdata = 0;

 * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };

 * Don't forget to initialize data not at file scope, i.e. within a function,

 * as gcc otherwise puts the data into the bss section and not into the init

 * section.

 * 

 * Also note, that this data cannot be "const".

 */

/* These are for everybody (although not all archs will actually