qcom_defconfig: enable livetree

qcom_defconfig: enable livetree

Qualcomm FDTs are on the larger size, and with the addition of DT
modifications during board_init() it makes sense to enable OF_LIVE
globally. The cost of building the tree should be offset by the
increased efficiency at which we can walk it.

Some rough measurements with CONFIG_BOOTSTAGE suggests that this might
add 0.1-0.2ms to the boot-to-console time. However the reset-to-reset
timer difference is in the range of 0.5ms so this could just be noise.

Suffice to say, no significant slow down.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>