Pin the device/sprd repo to revision a5507c0bea958453f5e640343e6c60530558ac9d to un-break Dolphin builds.
Revert "Pin the device/sprd repo to revision a5507c0bea958453f5e640343e6c60530558ac9d to un-break Dolphin builds."

This reverts commit d46e26099858c29eff762d0a77cee1d5eedba614.
Initial manifest for Raspberry Pi (rpi).