cheza: Enable MKBP keyboard protocol
This is used for passing button information from EC to AP.
BRANCH=None
TEST=make buildall -j
#define CONFIG_HOST_COMMAND_STATUS
#define CONFIG_HOSTCMD_SECTION_SORTED /* Host commands are sorted. */
#define CONFIG_MKBP_EVENT
+#define CONFIG_KEYBOARD_PROTOCOL_MKBP
#define CONFIG_BOARD_VERSION_GPIO
#define CONFIG_POWER_BUTTON
