mmc_test: block addressed cards

This patch fixes a bug in the multiblock write tests where the written
data is read back for verifying one block at a time.  The tests in
mmc_test assumes that all cards are byte addressable.

This will cause the multi block write tests to fail, leading the user of
the mmc_test driver thinking there is something wrong with the sdhci
driver they are testing.

The start address for the block is calculated as: blocknum * 512. For
block addressable cards the blocknum alone should be used.

Signed-off-by: Johan Kristell <johan.kristell@axis.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>