ata: ceva: Disable Device Sleep capability

Since CEVA controller does not support Device Sleep capability,
we need to clear that feature by clearing the DEVSLP bit in word78
of IDENTIFY DEVICE data. This patch does the same.

Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tejun Heo <tj@kernel.org>