nrf51: refine and extend known devices table

nrf51: refine and extend known devices table

The notation Gx0 in the nRF51 Series Compatibility Matrix indicates that
the specified HWID is valid only for build code 0 of each chip, and for
subsequent builds the HWID will be different.  Replace the Gx0 notation
with G0 throughout, and add the missing HWID for nRF51422 QFAC A1
(present on the newer nRF51 developer boards).

See: https://www.nordicsemi.com/eng/nordic/download_resource/41917/5/55913589
See: https://devzone.nordicsemi.com/question/30774/mapping-hwid-to-revision-information/

Change-Id: I79d842137d41342db35904867c48b06fbc6fbc70
Signed-off-by: Peter A. Bigot <pab@pabigot.com>
Signed-off-by: Angus Gratton <gus@projectgus.com>
Reviewed-on: http://openocd.zylin.com/2593
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>