mmc: block: register RPMB partition with the RPMB subsystem

Register eMMC RPMB partition with the RPMB subsystem and provide
an implementation for the RPMB access operations abstracting
the actual multi step process.

Add a callback to extract the needed device information at registration
to avoid accessing the struct mmc_card at a later stage as we're not
holding a reference counter for this struct.

Taking the needed reference to md->disk in mmc_blk_alloc_rpmb_part()
instead of in mmc_rpmb_chrdev_open(). This is needed by the
route_frames() function pointer in struct rpmb_ops.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Tested-by: Manuel Traut <manut@mecka.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20240814153558.708365-3-jens.wiklander@linaro.org


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>