configure: s/don't/do not/

The autoconf manual suggests not to use ' in messages.

I don't why they do, but it breaks syntax-highlighting.

Just remove the lone quote we have.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

# m68k specific configuration file

## select ARCH_SUPPORTS_32

## select ARCH_DEFAULT_32

## select ARCH_DEFAULT_BE

## select ARCH_SUPPORTS_WITH_CPU

##

## help The m68k architecture