Inspired by: https://os.mbed.com/forum/bugs-suggestions/topic/28059/
mbed-os-example-blinky compiles with 8 warnings for this target. Half of them from LWIP, half from NXP HAL.
@0xc0170, who's the right person from NXP to tag?
I can fix up the LWIP warnings.
@sarahmarshy PR is up for LWIP and the ethernet_api fixes.
ARM Internal Ref: MBOTRIAGE-152
5320 merged, should be resolved