In general we can't store things in the data section until we have inited
SDRAM. Some platforms allow this (e.g. those with SPL) but some don't. Move
the pointer to global_data so that it will work on all platforms.
Without this fix the serial port will not work prior to relocation with
driver model on some platforms.
Signed-off-by: Simon Glass <sjg@chromium.org>
469a579df2