ARM: 6980/1: mmci: use StartBitErr to detect bad connections

Stresstesting insert/remove of SD-cards can trigger
a StartBitErr. This made the driver to hang in forever
waiting for a non ocurring data timeout.

This bit and interrupt is documented in the original
PL180 TRM, just never implemented until now.

Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Reviewed-by: Linus Walleij <linus.walleij@stericsson.com>
Reviewed-by: Jonas Aberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>