serial: pic32: fix missing clk_disable_unprepare() on error in pic32_uart_startup()

Fix the missing clk_disable_unprepare() before return
from pic32_uart_startup() in the error handling case.

Fixes: 157b9394 ("serial: pic32_uart: Add PIC32 UART driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220525021204.2407631-1-yangyingliang@huawei.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>