ARM: qcom_defconfig: Enable MTD UBI driver

Enable MTD UBI driver for using partitions on top of NAND flash in
platforms like SDX55.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210118053853.56224-6-manivannan.sadhasivam@linaro.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>