modules: hal_nordic: Add nrf51 MDK defines needed to apply nrf51 erratas
modules: hal_nordic: Add nrf51 MDK defines needed to apply nrf51 erratas

Add nrf51 MDK defines needed to correctly select the nrf51 erratas
needed on the specific SoCs. The nrf51_erratas.h header file only uses
these defines to check which erratas should be applied.

Signed-off-by: Joakim Andersson <cf0fcab5d38d6e132e92a97bcb0bae257abf4936@nordicsemi.no>

finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr