mmc: cavium: Fix detection of block or byte addressing.

Use the mmc_card_is_blockaddr() function to properly detect if the
card uses byte or block addressing.

Signed-off-by: Steven J. Hill <Steven.Hill@cavium.com>
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>