devel/nasm: Update to 2.15.03

Update devel/nasm to 2.15.03
Add a patch to fix nasm's ELF_OSABI field when emitting object files [1]

Changelog:
https://nasm.us/doc/nasmdocc.html

PR: 245069 [1]
Submitted by: dim [1]
Reported by: unitrunker gmail com [1]
MFH: 2020Q3