devel/genromfs: mkfs equivalent for romfs filesystem

From: Tomasz CEDRO <tomek_at_cedro.info>
Date: Sun, 09 Jan 2022 23:22:09 UTC
Could anyone please take a look at this new port? :-)

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=259242

This is a dependency required by NuttX RTOS to build emulator image,
very useful for testing firmware as local binary on a build host :-)

Thank you in advance :-)
Tomek


-- 
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info