mmc: core: use mrq->sbc when sending CMD23 for RPMB

When sending out CMD23 in the blk preparation, the comment there
rightfully says:

	 * However, it is not sufficient to just send CMD23,
	 * and avoid the final CMD12, as on an error condition
	 * CMD12 (stop) needs to be sent anyway. This, coupled
	 * with Auto-CMD23 enhancements provided by some
	 * hosts, means that the complexity of dealing
	 * with this is best left to the host. If CMD23 is
	 * supported by card and host, we'll fill sbc in and let
	 * the host deal with handling it correctly.

Let's do this behaviour for RPMB as well, and not send CMD23
independently. Otherwise IP cores (like Renesas SDHI) may timeout
because of automatic CMD23/CMD12 handling.

Reported-by: Masaharu Hayakawa <masaharu.hayakawa.ry@renesas.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Clément Péron <peron.clem@gmail.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>