Input: wistron - declare keymaps as initdata

As the number of keymaps increases and is very unlikely to
reduce, this patch helps to reduce memory consumption by
declaring all keymaps as __initdata and copying right keymap
during DMI detection. On x86 this make the module size at
runtime going from 10616 to 9428: a bit more than 1kb saved.

Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>