mmc: core: Remove struct mmc_context_info

mmc: core: Remove struct mmc_context_info

The 'mmc_context_info' structure is unused.

It has been introduced in:

  - commit 2220eedfd7ae ("mmc: fix async request mechanism for sequential
    read scenarios")

in 2013-02 and its usages have been removed in:

  - commit 126b62700386 ("mmc: core: Remove code no longer needed after the
    switch to blk-mq")
  - commit 0fbfd1251830 ("mmc: block: Remove code no longer needed after
    the switch to blk-mq")

in 2017-12.

Now remove this unused structure.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Link: https://lore.kernel.org/r/232106a8a6a374dee25feea9b94498361568c10b.1724246389.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>