target/mips: Merge 32-bit/64-bit Release6 decodetree definitions

We don't need to maintain 2 sets of decodetree definitions.
Merge them into a single file.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210801234202.3167676-4-f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
4 files changed