IMX5 Removal

From: Kyle Evans <kevans_at_FreeBSD.org>
Date: Tue, 12 Sep 2023 18:19:12 UTC
Hi,

manu@ already removed the IMX5 kernel configs, but I'm now proposing we 
also remove the associated code specific to IMX5* SoCs:

https://reviews.freebsd.org/D41836

This comes after wasting time tweaking it for changes off in general 
infrastructure and quickly realizing that I can't even build-test those 
changes without going down another rabbit hole, which imo doesn't 
benefit anyone.

Thanks,

Kyle Evans