rpcrt4: Update TODO list.

Out-of-memory check is performed by NdrAllocate and so isn't required to 
be done in the unmarshalling functions.

dlls/rpcrt4/ndr_marshall.c

@@ -25,8 +25,7 @@
  *  - transmit_as/represent as
  *  - Multi-dimensional arrays
  *  - Conversion functions (NdrConvert)
- *  - Checks for integer addition overflow
+ *  - Checks for integer addition overflow in base type and user marshall functions
- *  - Checks for out-of-memory conditions
  */
 
 #include <stdarg.h>