[oe] Dropping armv5 and armv5e tunes in 2.7

[Khem Raj]

Hello All

You might have noticed a recent commit in gcc trunk

https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b232e6b58e3766bc66fe08fdb7bcba1bdadda8a2

Which removed support for deprecated -march=armv5 and armv5e, this
will be released along with gcc-9 release which is upcoming and we
might be able to add gcc9 to 2.7 release or 2.8 release for sure.

We still have non-thumb tunes for armv5 and armv4 in our tune pack, I
would like to propose a patch to remove them.

Secondly, I would also like to drop armv4t, and keep armv5te as lowest
supported tune, I know some of us do have machines using armv4t, if
you still maintain them and have need to keep armv4t going, please
chime into this thread.

I have also already posted a related patch here

https://patchwork.openembedded.org/patch/157529/

which uses 't' variants for -mtune explicitly for armv4 and armv5 tunes.

I will prepare patches if there is agreement here, and a no reply is
deemed to be 'yes' :)

Thanks
-Khem