arm64: mvebu: Update bubt command MMC block device access

arm64: mvebu: Update bubt command MMC block device access

Update the MMC block device access code in bubt command
implementation according to the latest MMC driver changes.

Change-Id: Ie852ceefa0b040ffe1362bdb7815fcea9b2d923b
Signed-off-by: Konstantin Porotchkin <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Nadav Haklai <[email protected]>
Cc: Neta Zur Hershkovits <[email protected]>
Cc: Omri Itach <[email protected]>
Cc: Igal Liberman <[email protected]>
Cc: Haim Boot <[email protected]>
Cc: Hanna Hawa <[email protected]>