target-mips: fix comments about SUB/DSUB

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/target-mips/translate.c b/target-mips/translate.c
index e96fe60..2c163e0 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -1590,7 +1590,7 @@
             tcg_temp_free(t2);
             tcg_gen_brcondi_tl(TCG_COND_GE, t1, 0, l1);
             tcg_temp_free(t1);
-            /* operands of same sign, result different sign */
+	    /* operands of different sign, first operand and result different sign */
             generate_exception(ctx, EXCP_OVERFLOW);
             gen_set_label(l1);
             gen_store_gpr(t0, rd);
@@ -1665,7 +1665,7 @@
             tcg_temp_free(t2);
             tcg_gen_brcondi_tl(TCG_COND_GE, t1, 0, l1);
             tcg_temp_free(t1);
-            /* operands of same sign, result different sign */
+	    /* operands of different sign, first operand and result different sign */
             generate_exception(ctx, EXCP_OVERFLOW);
             gen_set_label(l1);
             gen_store_gpr(t0, rd);