Implement LPC1768 USB abort function
Implement LPC1768 USB abort function

Implement the USB abort function so interrupts wont fire for a
transfer that has been aborted. The transfer may still take place
but the buffer passed into endpoint_write or endpoint_read will not
be used.

andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,andcor02/mbed-os,mbedmicro/mbed,andcor02/mbed-os,kjbracey-arm/mbed,kjbracey-arm/mbed,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed,mbedmicro/mbed,andcor02/mbed-os,kjbracey-arm/mbed,mbedmicro/mbed