[PATCH] Input: add modalias support

Here's the patch for modalias support for input classes.  It uses
comma-separated numbers, and doesn't describe all the potential keys (no
module currently cares, and that would make the strings huge).  The
changes to input.h are to move the definitions needed by file2alias
outside __KERNEL__.  I chose not to move those definitions to
mod_devicetable.h, because there are so many that it might break compile
of something else in the kernel.

The rest is fairly straightforward.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
CC: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>