mmc: octeontx2: calibrate tap delay

commit bd2f8b3927a6e775d9eb794ec871c6a89a4fc67e from
git@git.assembla.com:cavium/WindRiver.linux.git

The eMMC/SD interface supports a variety of devices
with board configurations and different timing
requirements. Timing is specified via the MIO_EMM_TIMING
register which controls the programmable delay lines.
Each delay line can be programmed to one of 64 taps.
The MIO_EMM_CALB register is used to calibrate these
delay lines and allows software to calculate how much
delay each tap represents. The results of the calibration
can be found in the MIO_EMM_TAP register.

Change-Id: Id3dc555bcab2590d26ee6b57b33ab4f1862e1972
Signed-off-by: Sujeet Baranwal <sujeet.baranwal@cavium.com>
Reviewed-on: https://sj1git1.cavium.com/8536


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/+/26902


Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>