SDS: Fix CR device to properly update status after a disconnect EOM

Experimentation with the SDS 9 Series Algol compiler found a problem in
the card reader.

The Algol card input function reads a complete card with the usual EOM
and WIM loop followed by a disconnect EOM.

A final service is requested after the last column is read to signal
that the card has passed through the reader. If the disconnect EOM
occurs before this service, it cancels it and shuts down the request
as it ought to.  However, the disconnect EOM does not reset the status
READING flag and a subsequent Reader Ready Test fails and loops waiting
for the disconnected reader to become ready.

This change fixes the disconnect EOM case to reset the uptr->STATUS and
end of record flag, cr_eor.

SDS/sds_cr.c

@@ -220,6 +220,8 @@ t_stat cr_devio (uint32 fnc, uint32 inst, uint32 *dat) {
         case IO_DISC:                                   /* disconnect */
             xfr_req = xfr_req & ~XFR_CR;                /* clr xfr flag */
             sim_cancel (uptr);                          /* deactivate unit */
+            cr_eor = 0;
+            uptr->STATUS = 0;
             break;
         case IO_SKS:                                    /* SKS */
             new_ch = I_GETSKCH (inst);                  /* get chan # */