Input: dm355evm_keys - fix kconfig symbol names

The keypad driver for the DM355 EVM got slightly broken as it merged,
since it moved from input/keyboard to input/misc and its Kconfig
symbol changed.  This patch copes with the changed Kconfig symbol.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>