dm: serial: Move current serial port pointer to global_data

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>
2 files changed