usr.bin/elf2aout build warning fix

[aprieger_llnw.com]

Summary

usr.bin/elf2aout (Convert ELF binary to a.out format) build warning fix

[aprieger_llnw.com]

Changelog:
Pre-fix warnings are at: https://gist.github.com/aprieger-llnw/ec32a64f35be3e4f0d250da53310ea27

1. usr.bin/elf2aout/elf2aout.c
   • Warnings:
     • warning: cast from 'char *' to 'Elf64_Phdr *' increases required alignment from 1 to 8 [-Wcast-align]
   • Fixes:
     • added the explicit modifier "void *" to the casting in order to force the alignment

[sbruno]

@emaste Is this "ok" to commit or is this masking something else going on?

[emaste]

Superseded by rS357627