方案使用8M的spi flash,去掉Uboot和kernel剩余大概在6M；方案里面不需要网络模块，生成release版本的文件系统，再裁剪掉网络部分以及一些不需要，文件系统在25M左右，生成的ubifs_ipnc.bin文件有15M，还是很大，裁剪后的filesys的大小情况如下：
0 ../target/filesys/linuxrc
4.0K ../target/filesys/boot
4.0K ../target/filesys/env.sh
4.0K ../target/filesys/proc
4.0K ../target/filesys/sys
4.0K ../target/filesys/tmp
8.0K ../target/filesys/dev
44K ../target/filesys/media
64K ../target/filesys/var
68K ../target/filesys/mnt
292K ../target/filesys/home
500K ../target/filesys/etc
664K ../target/filesys/bin
1.3M ../target/filesys/sbin
3.3M ../target/filesys/lib
6.4M ../target/filesys/usr
12M ../target/filesys/opt
最大的opt文件夹情况：
4.0K ../target/filesys/opt/ipnc/autorun_capturedisplay.sh
4.0K ../target/filesys/opt/ipnc/autorun_ipnc.sh
4.0K ../target/filesys/opt/ipnc/init.sh
4.0K ../target/filesys/opt/ipnc/ubifs_sync
4.0K ../target/filesys/opt/ipnc/upload
8.0K ../target/filesys/opt/ipnc/arm_loading
8.0K ../target/filesys/opt/ipnc/devmem
12K ../target/filesys/opt/ipnc/sbull.ko
32K ../target/filesys/opt/ipnc/scripts
40K ../target/filesys/opt/ipnc/dcc
40K ../target/filesys/opt/ipnc/g_file_storage.ko
48K ../target/filesys/opt/ipnc/reboot_ipnc
56K ../target/filesys/opt/ipnc/smart_mount
60K ../target/filesys/opt/ipnc/linux_prcm_ipcam
60K ../target/filesys/opt/ipnc/rs485_test
72K ../target/filesys/opt/ipnc/filesys_update
108K ../target/filesys/opt/ipnc/boot_proc
1.2M ../target/filesys/opt/ipnc/Appro_avi_save
1.2M ../target/filesys/opt/ipnc/kermod
1.3M ../target/filesys/opt/ipnc/bin
7.4M ../target/filesys/opt/ipnc/firmware
opt下firmware最大，采取的是low power模式，firmware只有ipnc_rdk_fw_m3video.xem3，ipnc_rdk_fw_m3vpss.xem3，这两个7.4M的文件还能减少吗，或者还可以裁哪些
