Describe the bug
RNDIS example PR #287 may not work with all ports, following is port that work

• Microchip SAMD
• Nordic nRF52840
• Nuvoton NUC126
• Nuvoton NUC505
• STM32 FSDev
• STM32 (Synopsys)
• iMX RT1010 work on windows/Linux/macOS (Ubuntu 18.04, Ubuntu 14.04, Windows 7, Windows 10, macOS High Sierra 10.13.16) with gcc 9.2.1 (ARM 2019-q4) after increased stack size from 0x400 to 0x800

Ports that tested and not work

• Microchip SAMG
• NXP iMX RT: RT1020-RT1064 work with Windows VM, but doesn't seem to work with native ubuntu 20.04 (more tests needed)
• NXP lpc 18 / 43 /

Ports that haven't tested yet

• Nuvoton NUC120
• NXP LPC3511
• NXP LPC17/40
• Sony CXD56
• TI MSP430
• Fomu