mx53_loco: fix deadlock report from sdma_tx_submit() during boot

BugLink: http://bugs.launchpad.net/bugs/878701

Adjust to use spin_lock_irqsave()/spin_unlock_irqresotre(), so to
make it safe when called from interrupt context.
Signed-off-by: NHaitao Zhang <haitao.zhang@linaro.org>
Signed-off-by: NEric Miao <eric.miao@linaro.org>
Signed-off-by: NRichard Zhao <richard.zhao@linaro.org>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NVinod Koul <vinod.koul@linux.intel.com>