mmc: octeontx2: track & apply CMD6 bus changes ASAP

commit e91f1d645fcd073223289f141ef4369150fae118 from
git@git.assembla.com:cavium/WindRiver.linux.git

When mmc/core issued CMD6 to change bus width, timing
and encoding style, we must apply the change to our
hardware immediately.
Previous code applied it eventually, but meanwhile
mmc/core code had been polling status with CMD13
under the old protocol, which may have been causing
HS400 transitions to fail.

To apply the change immediately, at IRQ-time, the host
pointer is set on every outgoing request, so IRQ handler
can find context (the associated cvm_mmc_slot) for a
successfully executed CMD6, and the MIO_EMM_SWITCH value
it should apply, to bring the host hardware & target card
into alignment.

CMD6 can potentially set/clear individual bits of ext_csd,
which would require caching the ext_csd entries for the 3
bytes we track, to reconstruct the meaning.
But fortunately mmc/core only issues a full-byte assignment
(action=3) for the power/width/timing properties we mirror.
Should this change, more work may be needed here.

Change-Id: I13df44e96d61a071b73f1d3f014ff0276ba51135
Signed-off-by: Peter Swain <pswain@marvell.com>
Signed-off-by: Sujeet Baranwal <sbaranwal@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/8546


Reviewed-by: Sunil Kovvuri Goutham <Sunil.Goutham@cavium.com>
Tested-by: Sunil Kovvuri Goutham <Sunil.Goutham@cavium.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/26909


Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
[RQ: remove unused var flags.]
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>