qseecom: improve input validatation for qseecom_send_service_cmd

Make change to improve input validation on request and response
buffers' address and length for qseecom_send_service_cmd.

Change-Id: I047e3264333d767541e43b7dadd1727232fd48ef
Signed-off-by: Zhen Kong <zkong@codeaurora.org>