Coachz: Enable CONFIG_LTO
Coachz is down to 100's of bytes of free flash on ToT.  Enable LTO to
free up about 9k in flash space.
BRANCH=None
TEST=make -j BOARD=coachz shows 9k+ free flash
#define CONFIG_FLASH_SIZE_BYTES (512 * 1024) /* 512KB internal spi flash */
/* Save some flash space */
+#define CONFIG_LTO
#define CONFIG_USB_PD_DEBUG_LEVEL 2
#undef CONFIG_CMD_FLASHINFO
#undef CONFIG_CMD_MMAPINFO
