serial: 8250_bcm7271: balance clk_enable calls

serial: 8250_bcm7271: balance clk_enable calls

The sw_baud clock must be disabled when the device driver is not
connected to the device. This now occurs when probe fails and
upon remove.

Fixes: 41a469482de2 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Reported-by: XuDong Liu <m202071377@hust.edu.cn>
Link: https://lore.kernel.org/lkml/20230424125100.4783-1-m202071377@hust.edu.cn/
Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230427181916.2983697-2-opendmb@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>