travis: kernel clone takes too long

.travis.yml

@@ -11,9 +11,6 @@ matrix:
   include:
   - env: ARCH=arm SYSTEM=beaglebone-black
   - env: ARCH=arm SYSTEM=linksys-nslu2
-  - env: ARCH=arm SYSTEM=raspberry-pi
-  - env: ARCH=arm SYSTEM=raspberry-pi2
-  - env: ARCH=arm SYSTEM=raspberry-pi3
   - env: ARCH=avr32 SYSTEM=atmel-ngw100
   - env: ARCH=avr32 SYSTEM=grasshopper
   - env: ARCH=cris SYSTEM=foxboard-lx832