fix(boards): V6X-RT increase IOB buffers

Enable IOB throttle to avoid RX starvation and increase amount
of IOB buffers since we've got 4 interfaces that uses IOB

Author: PetervdPerk-NXP

boards/px4/fmu-v6xrt/nuttx-config/nsh/defconfig

@@ -142,8 +142,9 @@ CONFIG_IMXRT_USDHC1_INVERT_CD=y
 CONFIG_IMXRT_USDHC1_WIDTH_D1_D4=y
 CONFIG_INIT_ENTRYPOINT="nsh_main"
 CONFIG_INIT_STACKSIZE=2944
-CONFIG_IOB_NBUFFERS=24
-CONFIG_IOB_THROTTLE=0
+CONFIG_IOB_NBUFFERS=256
+CONFIG_IOB_NCHAINS=196
+CONFIG_IOB_NOTIFIER=y
 CONFIG_IPCFG_BINARY=y
 CONFIG_IPCFG_CHARDEV=y
 CONFIG_IPCFG_PATH="/fs/mtd_net"