Ensure that IG (Global) bit is reset in MAC address for K64F and others

See IEE 802.3-2002, Section 3.2.3(b)
remove useless assert line
[HAL][NRF51822] enable I/O mapping and peripheral dynamic assignment for I2C and SPI
Add repeater pinmode
[HAL][KSDK] Fix first serial char not being sent

The K64F/K22F didn't send the first char. I don't know why exactly, but
any type of reading a status register seems to fix it. And this extra
line at least makes sense. Now it works correctly.
Merge pull request #662 from xiongyihui/nrf51822

Targets: NRF51822 -  enable I/O mapping and peripheral dynamic assignment for I2C and SPI
Merge pull request #663 from bikeNomad/master

Ensure that IG (Global) bit is reset in MAC address for K64F and others
Merge pull request #673 from Wind0r/fix_lpc1768_repeatmode

Targets: LPC176X - Add repeater pinmode
Remove duplicate target definitions
Merge pull request #677 from Sissors/ksdk

Targets: Freescale KSDK - Fix first serial char not being sent