uboot-imx

arm: rmobile: Support build with gcc-4.6 or later

Latest rmobile code was tested by using old gcc (gcc-4.4).
When we use gcc-4.6 (or later), the build is made, but does not work.
This solves a problem not to work by add -march=armv5 to compiple option
when we built in gcc-4.6 (or later).
I tested by linaro's compiler version 2012.04-20120426.

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