Add OSTM timer driver for RZ/A1 SoC. The IP is very different
from the R-Car Gen2/Gen3 one already present in the tree, hence
a custom driver.
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Chris Brandt <chris.brandt@renesas.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
