[MMC] sdhci: remove duplicate error message

When there is remaining blocks untransferred, we get two error messages saying
almost the same thing.  Make sure at most one is shown.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>