硬件Rev C
软件：使用Buildroot编译，内核使用ti-sdk-am335x-0.7版安装后的提供版本，
编译内核后，单独加载g_ether,g_serial,g_mass_storage，PC端驱动都能识别，但是在加载g_multi时，存储功能识别不了。
modprobe g_mass_storage file=/dev/mmcblk0p1可以识别到U盘
g_multi加载过程日志：
modprobe g_multi file=/dev/mmcblk0p1 cdrom=0 stall=0 removable=1 nofua=1 iSeri
alNumber=C0-2814BBBK8499 iManufacturer=Circuitco iProduct=BeagleBoneBlack host_addr=78:
A5:04:C1:A4:56
[ 793.539316] using random self ethernet address
[ 793.546153] using random host ethernet address
[ 793.551707] using host ethernet address: 78:A5:04:C1:A4:56
[ 793.557607] using random self ethernet address
[ 793.563414] using random host ethernet address
[ 793.568147] using host ethernet address: 78:A5:04:C1:A4:56
[ 793.576745] usb0: HOST MAC 78:a5:04:c1:a4:56
[ 793.582746] usb0: MAC ae:64:96:c5:b7:74
[ 793.587832] Number of LUNs=8
[ 793.591957] Mass Storage Function, version: 2009/09/11
[ 793.597443] LUN: removable file: (no medium)
[ 793.602958] Number of LUNs=1
[ 793.606747] LUN: removable file: /dev/mmcblk0p1
[ 793.612703] Number of LUNs=1
[ 793.616403] unwind: Index not found bf0bd32c
[ 793.620979] unwind: Index not found bf0bd32c
[ 793.625543] unwind: Index not found bf0bd32c
[ 793.630142] unwind: Index not found bf0bd32c
[ 793.634946] unwind: Index not found bf0bd32c
[ 793.641000] unwind: Index not found bf0bd32c
[ 793.645575] unwind: Index not found bf0bd32c
[ 793.650133] unwind: Index not found bf0bd32c
[ 793.654718] unwind: Index not found bf0bd32c
[ 793.659450] unwind: Index not found bf0bd32c
[ 793.671639] g_multi gadget: Multifunction Composite Gadget
[ 793.677450] g_multi gadget: g_multi ready
# [ 793.973427] g_multi gadget: high-speed config #1: Multifunction with RNDIS
发现其中的iSerialNumber如果随便填写的话PC端驱动识别不了，现在的那个序号是使用原生的系统进入后读出来的。
而我用Buildroot编译的系统没有支持EEPROM，所以读不出序号。
如果不填写序号的话，在PC端识别出multifunction compatible gadget，PC端驱动无法安装
