configs/qemu_*: unbreak after version bump

Commit 2c859079 (configs/qemu: bump relevant config version) renamed
a number of linux configuration files, but forgot to update the defconfigs.

Tests shows that atleast arm versatile doesn't boot with 3.11, so rename
the linux configuration files back rather than adjusting the defconfigs.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>