target/mips: Remove microMIPS BPOSGE32 / BPOSGE64 unuseful cases

These switch cases for the microMIPS BPOSGE32 / BPOSGE64 opcodes have
been added commit 3c824109da0 ("target-mips: microMIPS ASE support").
More than 11 years later it is safe to assume there won't be added
soon. The cases fall back to the default which generates a RESERVED
INSTRUCTION, so it is safe to remove them.
Functionally speaking, the patch is a no-op.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210617174323.2900831-8-f4bug@amsat.org>

target/mips/tcg/translate.c

@@ -14076,8 +14076,6 @@ enum {
     BGEZALS = 0x13,
     BC2F = 0x14,
     BC2T = 0x15,
-    BPOSGE64 = 0x1a,
-    BPOSGE32 = 0x1b,
     /* These overlap and are distinguished by bit16 of the instruction */
     BC1F = 0x1c,
     BC1T = 0x1d,
@@ -16121,10 +16119,6 @@ static void decode_micromips32_opc(CPUMIPSState *env, DisasContext *ctx)
                 generate_exception_err(ctx, EXCP_CpU, 1);
             }
             break;
-        case BPOSGE64:
-        case BPOSGE32:
-            /* MIPS DSP: not implemented */
-            /* Fall through */
         default:
             MIPS_INVAL("pool32i");
             gen_reserved_instruction(ctx);