mmc: moxart: Remove unused variable 'dma_time' and 'pio_time'

mmc: moxart: Remove unused variable 'dma_time' and 'pio_time'

Fixes the following W=1 kernel build warning(s):

drivers/mmc/host/moxart-mmc.c:257:7: warning: variable ‘dma_time’ set
but not used
drivers/mmc/host/moxart-mmc.c:395:7: warning: variable ‘pio_time’ set
but not used

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/1617357231-93064-1-git-send-email-yang.lee@linux.alibaba.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>