configs/qemu: bump relevant config versions

arm_nuri needs some DT fixups to switch to the 3.11.x series since it's
now default for that kernel defconfig.

[Peter: adjust comment in sparc defconfig to match]
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>