drivers: soc: Initialize return var to default value

Initialize return variable to default invalid handle before
it is used. During an error condition it sets correct
error code to avoid returning uninitialized return value.

Change-Id: Ibad70b1bb364b60439c4988e318105a733396db8
Signed-off-by: Vikram Panduranga <vpandura@codeaurora.org>
CRs-Fixed: 1059495