Revert "imx8qxp_mek: Disable CONFIG_DISPLAY_CPUINFO"

This reverts commit c5bbfaf0.

Disabling CONFIG_DISPLAY_CPUINFO was a temporary solution to get
the v2018.11 release out. Now the merge window opens, revert it.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>