Klocwork check null before dereference in acl_svm.cpp

[haoxian2]

Fixed the following Klocwork issue:

1. Pointer 'context->svm_list' returned from call to function 'malloc' at line 147 may be NULL and will be dereferenced at line 149.
   Verifying that malloc appropriately allocated the memory. The size of malloc is not user defined, therefore an assert is more appropriate.

[pcolberg]

Klocwork issues resolved in commit d845c2b:

---------------------------------------------------------------------------
124 (Local) /__w/fpga-runtime-for-opencl/fpga-runtime-for-opencl/src/acl_svm.cpp:149 NPD.FUNC.MUST (1:Critical) Analyze
Pointer 'context->svm_list' returned from call to function 'malloc' at line 147 may be NULL and will be dereferenced at line 149.
  * acl_svm.cpp:147: 'context->svm_list' is assigned the return value from function 'malloc'.
  * acl_svm.cpp:149: 'context->svm_list' is explicitly dereferenced.
Current status 'Analyze'

Summary: 1 Local
1 Total Issue(s)