power: reset: Disable SDI when dload mode is disabled

Add function to auto disable the SDI when the ramdump is disabled.
And make the device do hard reset at the same time.

Change-Id: I14e2d13792ef535364a082cdaed0b79c262ecfe5
Signed-off-by: Lijuan Gao <lijuang@codeaurora.org>
Signed-off-by: Mukesh Ojha <mojha@codeaurora.org>
[mojha@codeaurora.org: Fixed merged conflict,
redefination of download_mode variable and mismatch function
prototype of dload_set]