board: kevin: undefined i2c_xfer command
Save some space on kevin.
BRANCH=master
TEST=Can compile kevin with perform_calib addition.
#undef CONFIG_CMD_ACCELSPOOF
#undef CONFIG_CMD_FLASHINFO
+#undef CONFIG_CMD_I2C_XFER
/* Gru is especially limited on code space */
#ifdef BOARD_GRU
#undef CONFIG_CMD_IDLE_STATS
-#undef CONFIG_CMD_I2C_XFER
#undef CONFIG_USB_PD_LOGGING
#undef CONFIG_CMD_SHMEM
#undef CONFIG_CMD_USBMUX
