mmc: mmci: Use a switch statement machine

As is custom, use a big switch statement to transition
between the edges of the state machine inside
the ux500 ->busy_complete callback.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230405-pl180-busydetect-fix-v7-8-69a7164f2a61@linaro.org


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>