Removed checks for NULL returns after osi_calloc() / osi_malloc()

Removed explicit checks for NULL pointer returns after calls
to osi_calloc() and osi_malloc(), because those are not needed.
If the memory allocation fails, osi_calloc() and osi_malloc()
will trigger an assert.

Bug: 27048759
Change-Id: I2791eb2f69c08f991f8fcdef10e101a41568cd95