arm: rmobile: Update README.rmobile

Add infomation of Lager and Koelsh board, and R-Car.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
1 file changed