qseecom: improve error checks in qseecom_probe()

Make change in qseecom_probe() to improve the error return value
checks on some subfunctions, and free memory allocated within
qseecom_retrieve_ce_data.

CRs-fixed: 1075082
Change-Id: I971e555ec8d02ccf4382e83132a696b065a8ff12
Signed-off-by: Zhen Kong <zkong@codeaurora.org>