configure, meson: deprecate 32-bit MIPS

The mipsel architecture is not available in Debian Trixie, and it will
likely be a hard failure as soon as we drop support for the old Rust
toolchain in Debian Bookworm.  Prepare by deprecating 32-bit little
endian MIPS in QEMU 9.2.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
3 files changed