mmc: block: Tag is_rpmb as bool

The variable is_rpmb is clearly a bool and even assigned true
and false, yet declared as an int.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/block.c

@@ -443,7 +443,7 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
 	struct mmc_request mrq = {};
 	struct scatterlist sg;
 	int err;
-	int is_rpmb = false;
+	bool is_rpmb = false;
 	u32 status = 0;
 
 	if (!card || !md || !idata)