bcm_sta: update kernel 3.10 support patch

Signed-off-by: Stephan Raue <stephan@openelec.tv>
bcm_sta: add patch to support kernel 3.15

Signed-off-by: Stephan Raue <stephan@openelec.tv>
projects/*/linux: enable and build with kernel 3.15 by default (except for Rpi and Cubox-i)

Signed-off-by: Stephan Raue <stephan@openelec.tv>