Renaming these specs should cause less trouble than usual since
most people are likely using the rasp-pi2 spec even for RPi3.
[ChangeLog][Platform Specific Changes][Linux] The Raspberry Pi 3
device specs have been renamed from linux-rpi3-* to linux-rasp-pi3-*
in order to follow the pattern of the RPi 1 and 2 specs.
Change-Id: I7d1ed6a4665078af9a4cbbe4c38b5fac760d03f9
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
