irqchip/aspeed-scu-ic: Fix an IS_ERR() vs NULL check

of_iomap() doesn't return error pointers, it returns NULL.  Fix the error
checking to check for NULL pointers.

Fixes: 86cd4301c285 ("irqchip/aspeed-scu-ic: Refactor driver to support variant-based initialization")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
1 file changed