ARM: 7214/1: mmc: mmci: Fixup handling of MCI_STARTBITERR

The interrupt was previously enabled and then correctly cleared.
Now we also handle it correctly.

Cc: <stable@vger.kernel.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>