power: smb1355: Fix SMB1355 disable logic

For disabling SMB1355, we switch SMB1355 to command control mode.
However, by default, command control bit is set to enable SMB1355,
resulting in enablement of SMB1355. Fix this by initializing command
control bit to disable SMB1355.

Change-Id: I290cb980d58ddc0118c24c46433c20a13cad0dab
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>