According to the CC1310LP design files, the flash on it is the same as the flash on the CC2650 LP (MX25R8035F 8Mbit). However, the flash on some CC1310 LPs reportedly identifies itself as the 16Mbit one (MX25R1635F). Instruction sets are identical, we simply need to tell the driver to recognise this part's Device ID.
This commit creates a `common` directory, aimed to host drivers supported by multiple boards of the CC13xx/CC26xx family.
We move the Sensortag SPI and External Flash drivers to this location and we change the Sensortag build system to pull the respective files from therein.