efidp_duplicate_extra(): error if our allocation is too small.
efidp_duplicate_extra(): error if our allocation is too small.

Covscan believes we might pass 0 to calloc(), though I suspect this is
because it doesn't fully grok add().

Signed-off-by: Peter Jones <2e0a021e603479ff81838c00c3b770daca4e0214@redhat.com>

rhinstaller/efivar,rhboot/efivar,vathpela/efivar-devel,rhinstaller/efivar,rhboot/efivar