Fix ARI violations in mips-linux-nat.c and mips-tdep.c

gdb/ChangeLog:

        * mips-linux-nat.c (mips_linux_read_description): Add missing i18n
        marker.
        * mips-tdep.c (mips_linux_reg_names): Improve comment to avoid ARI
        violation.

gdb/mips-linux-nat.c

@@ -447,7 +447,7 @@ mips_linux_read_description (struct target_ops *ops)
 	  have_dsp = 0;
 	  break;
 	default:
-	  perror_with_name ("ptrace");
+	  perror_with_name (_("ptrace"));
 	  break;
 	}
     }