misc/seabios: Update to 1.16.0; use binutils binaries

[jrm]

Summary

Upstream release information:

• https://www.seabios.org/Releases#SeaBIOS_1.15.0
• https://www.seabios.org/Releases#SeaBIOS_1.16.0

USE_BINUTILS=yes adjusts the environment with, e.g.,
OBJDUMP=${LOCALBASE}/bin/objdump, so that binaries from devel/binutils
are used to build ports. SeaBIOS, however, will not use these values,
so set MAKE_ARGS to ensure binaries from devel/binutils are used here.
This will fix the build when /usr/bin/llvm-objdump is linked to
/usr/bin/objdump. See PR 267854.

Test Plan

• poudriere testport on amd64 CURRENT system with and without llvm-objdump installed as /usr/bin/objdump succeeds
• testport on amd64/i386 releases are still running; will update when complete
• no runtime tests

[royger]

LGTM. Thanks for doing this.