mmc: sh-mmcif: final error path cleanup

Remove the error path items that are no longer needed. The mmc card-detect
code cleans up after itself (and registers with devm) and the host error
is the same as the clock disable.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>