mmc: queue: turn queue flags into bools

Instead of masking and setting two bits in the "flags" field
for the mmc_queue, just use two bools named "suspended" and
"new_request".

The masking and setting would likely have race conditions
anyways, it is better to use a simple member like this.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>