A previous patch I had removed the returns from vfe_disable() since we
didn't trap any meaningful errors. Konrad pointed out vfe_reset() could
return an error, which is true.

Trap the vfe_reset() error code and throw it up the callstack.
Suggested-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>