uefisign: handle empty sections
loader.efi has an empty set_Xfic section. Handle it correctly.
Sections: Idx Name Size VMA LMA File off Algn [...] 3 set_Xcom 00000168 00000000000d4000 00000000000d4000 000d0e00 2**2 CONTENTS, ALLOC, LOAD, DATA 4 set_Xfic 00000000 00000000000d4168 00000000000d4168 00000000 2**2 ALLOC, LOAD, DATA 5 .sdata 00000448 00000000000d5000 00000000000d5000 000d1000 2**2 CONTENTS, ALLOC, LOAD, DATA [...]
Reviewed by: trasz, dab
Reported by: andy.y.liu@dell.com
Tested by: andy.y.liu@dell.com
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D29606
(cherry picked from commit 12db51d20823a5e3b9e5f8a2ea73156fe1cbfc28)