esoc: Add check for possible null pointer returns

The call to kasprintf() can fail, with a failure to
allocate memory. Handle the condition appropriately.

CRs-Fixed: 1014400
Change-Id: I83d3a6c8bdfd7a104b88a3bedd50f49faeecd97a
Signed-off-by: Hanumant Singh <hanumant@codeaurora.org>