ARM: socfpga: Zap all the UART handling complexity

The UART reset handling is now done via reset framework using the
SoCFPGA reset driver. The UART console assignment is done using the
DM and console framework. Nuke all this comlexity, since it is just
duplicating the same functionality, badly.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Chin Liang See <chin.liang.see@intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>