RISC-V copyright assignment problems with the B extension work

[Nelson Chu]

Hi Guys,

I'm sorry to tell you the bad news that we meet the copyright
assignment problems recently.  After these days of discussion, we make
a very difficult decision to avoid any potential problems in the
future - we have to remove all B extension implementations of the
commit 2652cfad8d9d6ab05fe6296802ec499682a00749, from both binutils
mainline and 2.36 release branches.  We know that this will cause
inconvenience for many people, but it may be the best solution to make
sure any future copyright problems won't happen.

We need to get your permissions that remove the commit from 2.36
release, really sorry for the inconvenience.  Any suggestions and
feedback are appreciated.

Nelson