crypto: msm: Set command descriptor size to burst size multiple

Remove dummy command elements added for the DES/DES3 CBC algorithm.
In order for proved perfromance, the  descriptor (data and command)
size sent to the BAM needs to be multiple of burst size (set to 64B).

Change-Id: If9b0cef79f15da73b18d55c24c32f4c0b7b1216a
Signed-off-by: Mona Hossain <mhossain@codeaurora.org>