irqchip/wpcm450: Fix memory leak in wpcm450_aic_of_init()

If of_iomap() failed, 'aic' should be freed before return. Otherwise
there is a memory leak.

Fixes: fead4dd4 ("irqchip: Add driver for WPCM450 interrupt controller")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115092532.1704032-1-weiyongjun@huaweicloud.com