buildtools: check allocation error in pmdinfogen
buildtools: check allocation error in pmdinfogen

In func locate_pmd_entries(), pointer 'new' returned from call to func
'calloc' may be NULL. It is dereferenced without null point check.

Signed-off-by: Yong Wang <d43454047dd416473224614364813c3ab52b395d@zte.com.cn>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk