qcom_defconfig: set SYS_INIT_SP_BSS_OFFSET

Give us lots of room for the appended FDT.

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