Add a failure check after grub_calloc() call. If grub_calloc()
fails, e.g., due to memory allocation failure, it returns NULL.
Then using grub_efiemu_elfsyms, which will be NULL, later will
result in a NULL pointer dereference.
Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>
Reviewed-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>