Staging: sst: more copy_to_user() changes

Vinod wanted the copy_to_user() calls in this format:
	if (copy_to_user())
		retval = -EFAULT;
instead of this:
	retval = copy_to_user();
	if (retval)
		retval = -EFAULt;

I've done that for the whole intel_sst_app_interface.c file.  In the
process I noticed a couple more places that returned -EBUSY or -EAGAIN
instead of -EFAULT.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>