serial: Add Zynq serial driver

The driver is used on Xilinx Zynq platform.

Signed-off-by: Michal Simek <monstr@monstr.eu>
CC: Joe Hershberger <joe.hershberger@gmail.com>
CC: Marek Vasut <marex@denx.de>
Acked-by: Marek Vasut <marex@denx.de>
4 files changed