mdt_loader: check for overflow before allocating memory

Memory allocation is happening without checking the overflow.
This could lead to an unexpected results. Check for overflow
before allocating memory.

Change-Id: Icb513ebd8030976e3f0970e9542596f9c5917843
Signed-off-by: Murali Nalajala <quic_mnalajal@quicinc.com>
Signed-off-by: Srinivasarao Pathipati <quic_c_spathi@quicinc.com>