mmc: block: fix semicolon.cocci warnings

drivers/mmc/core/block.c:1929:3-4: Unneeded semicolon

 Remove unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci

CC: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>