arm: Treat arm946es as v5te

The arm946es is armv5te , so use -march=armv5te instead of armv4t.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Tom Rini <trini@konsulko.com>