Snapdragon 700 or newer is typically recommended. For Qualcomm devices, processors with 2 or more 'big cores' recommended.
Onboard graphics may work, but drivers may vary. Highly recommended to have 4 cores or more. Most modern Linux distributions should work given support for Dolphin's dependencies, and FreeBSD is unsupported but also may work.
Generally, these are the minimum recommended requirements for Dolphin. Every game has different requirements, some titles may require a powerful computer while some other titles may not.