mmc: sdhci: Fix strings broken across multiple lines

This is a trivial patch which fixes printed strings split across two
or more lines in the source. I tried to grep for some error output*,
but I couldn't find it easily because it was broken across multiple
lines. This patch makes my life easier.

* in particular "Timeout waiting for hardware interrupt."

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>