i2c-qup: Verify that mem resource exists prior to redirection

Redirection may cause a system crush in the case of a missing
memory resource specification. Now when reading a memory
resource from platform data, the return value is checked
before doing redirection on the resource.

Change-Id: Id4ef9c293f65935d6e3bd311720a1e66a2da8f35
Signed-off-by: Gilad Avidov <gavidov@codeaurora.org>