CVE-2026-98208: mmc: sdio_uart: fix xmit_fifo leak when the port table is full

In the Linux kernel, the following vulnerability has been resolved:

mmc: sdiouart: fix xmitfifo leak when the port table is full

sdiouartaddport() allocates the transmit fifo before claiming a slot in sdiouarttable[]. When all UARTNR slots are taken, it returns -EBUSY with the fifo still allocated, but the probe error path only kfree()s the port, leaking the transmit fifo.

Free the fifo in the failure path of sdiouartaddport() itself so the function retains nothing on error.