target/mips: Convert Rel6 LWLE/LWRE/SWLE/SWRE opcodes to decodetree

LWLE/LWRE/SWLE/SWRE (EVA) opcodes have been removed from
the Release 6. Add a single decodetree entry for the opcodes,
triggering Reserved Instruction if ever used.

Remove unreachable check_insn_opc_removed() calls.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-11-f4bug@amsat.org>
2 files changed