[FRDM-K64F] Fix FOPT EzPort bit documentation and set it to disable at start-up to
allow proper booting when powered from the K64F USB port. Refer to issue (#569).
Merge pull request #581 from hchanon/FRDM-K64F_FOPT_EzPort_Bit_Inverted

Targets: FRDM-K64F - Fix FOPT EzPort bit documentation and set it to disable