Revert "Revert "mmc: core: enable CMD19 tuning for DDR50 mode""

[chaitu236]

This reverts commit 43ccc9ea05d44f59fc231f5fc16acebb07017be7 which is no longer necessary as CMD19 tuning works for DDR50 mode in 6.1 kernels.

WI: 2113488

Testing

• [x] With swissbit 16G micro sd card oon a cRIO-9053, no "ddr50 tuning failed" log in dmesg
• [x] Added logs to mmc code to verify that tuning is happening and not being skipped.
• [x] Following log in dmesg confirming DDR50 mmc0: new ultra high speed DDR50 SDHC card at address 0001
• [x] Read speeds from the micro sd card in 43MB/s range which indicate DDR50 mode (and not high speed mode which is limited to 35MB/s)
• [x] Reproduced issue on the target on older kernel before the mmc patches were put in.

[kroeschl]

~Did we verify that this specific Swissbit card reproduced the tuning failure on an old kernel without this patch? Just in case this was a later revision of the card or something like that.~

Oops, that's in the PR description. I would suggest that we test with an old, un-patched kernel in case this was a later hardware rev of the SD card.

[chaitu236]

I would suggest that we test with an old, un-patched kernel in case this was a later hardware rev of the SD card.

I tested with an unpatched 4.9 kernel and could reproduce the issue.

[bstreiff]

Merged into nilrt/master/6.1 as fa76b53408dd.