Input: dell-wmi - switch to using sparse keymap library

Instead of implementing its own version of keymap hanlding switch over to
using sparse keymap library.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

drivers/platform/x86/Kconfig

@@ -92,6 +92,7 @@ config DELL_WMI
 	tristate "Dell WMI extras"
 	depends on ACPI_WMI
 	depends on INPUT
+	select INPUT_SPARSEKMAP
 	---help---
 	  Say Y here if you want to support WMI-based hotkeys on Dell laptops.