target-sh4: MMU: fix mem_idx computation

The mem_idx is wrongly computed. As written in target-sh4/cpu.h, mode 0
corresponds to kernel mode (SR_MD = 1), while mode 1 corresponds to user
mode (SR_MD = 0).

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/target-sh4/translate.c b/target-sh4/translate.c
index 8f0a986..bff3188 100644
--- a/target-sh4/translate.c
+++ b/target-sh4/translate.c
@@ -1905,7 +1905,7 @@
     ctx.bstate = BS_NONE;
     ctx.sr = env->sr;
     ctx.fpscr = env->fpscr;
-    ctx.memidx = (env->sr & SR_MD) ? 1 : 0;
+    ctx.memidx = (env->sr & SR_MD) == 0 ? 1 : 0;
     /* We don't know if the delayed pc came from a dynamic or static branch,
        so assume it is a dynamic branch.  */
     ctx.delayed_pc = -1; /* use delayed pc from env pointer */