target-mips: fix CP0.BadVAddr by stopping translation on Address Error

CP0.BadVAddr is supposed to capture the most recent virtual address that caused
the exception. Currently this does not work correctly for unaligned instruction
fetch as translation is not stopped and CP0.BadVAddr is updated with subsequent
addresses.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>

target-mips/translate.c

@@ -18438,6 +18438,7 @@ static void decode_opc(CPUMIPSState *env, DisasContext *ctx)
     if (ctx->pc & 0x3) {
         env->CP0_BadVAddr = ctx->pc;
         generate_exception_err(ctx, EXCP_AdEL, EXCP_INST_NOTAVAIL);
+        ctx->bstate = BS_STOP;
         return;
     }