If we try to build this file in a multiplatform configuration with
ARMv6 enabled, gas complains about the dsb operation being undefined.
Adding -march=armv7-a is safe because that code is only ever run
on ux500, which is Cortex-A9.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>