Input: wistron_btns - switch to using sparse keymap library

The keymap manipulation code was split into a library module,
so let's make us of it.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index a9bb254..d25ecbb 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -80,6 +80,7 @@
 	tristate "x86 Wistron laptop button interface"
 	depends on X86 && !X86_64
 	select INPUT_POLLDEV
+	select INPUT_SPARSEKMAP
 	select NEW_LEDS
 	select LEDS_CLASS
 	select CHECK_SIGNATURE