hw/sd: ssi-sd: Fix the wrong command index for STOP_TRANSMISSION

hw/sd: ssi-sd: Fix the wrong command index for STOP_TRANSMISSION

This fixes the wrong command index for STOP_TRANSMISSION, the
required command to interrupt the multiple block read command,
in the old codes. It should be CMD12 (0x4c), not CMD13 (0x4d).

Fixes: 775616c3ae8c ("Partial SD card SPI mode support")
Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210123104016.17485-10-bmeng.cn@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>