hw/sd/sdcard: Reset both start/end addresses on error

From the Spec "4.3.5 Erase":

  The host should adhere to the following command
  sequence: ERASE_WR_BLK_START, ERASE_WR_BLK_END and
  ERASE (CMD38).

  If an erase (CMD38) or address setting (CMD32, 33)
  command is received out of sequence, the card shall
  set the ERASE_SEQ_ERROR bit in the status register
  and reset the whole sequence.

Reset both addresses if the ERASE command occured
out of sequence (one of the start/end address is
not set).

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201015063824.212980-5-f4bug@amsat.org>

hw/sd/sd.c

@@ -755,6 +755,8 @@ static void sd_erase(SDState *sd)
     if (sd->erase_start == INVALID_ADDRESS
             || sd->erase_end == INVALID_ADDRESS) {
         sd->card_status |= ERASE_SEQ_ERROR;
+        sd->erase_start = INVALID_ADDRESS;
+        sd->erase_end = INVALID_ADDRESS;
         return;
     }