for target Arch BLE, enable I/O mapping for I2C, SPI and UART

1. enable nRF51822 I/O mapping for I2C, SPI and UART
2. make I2C use I2C0 and SPI use SPI1, as I2C0 & SPI0 (or I2C1 & SPI1) share the same address and can't be used at the same time

The change only affects target Arch BLE
This feels arbitrary. Why use I2C0 for I2C, but SPI1 for SPI (instead of SPI0)?