platform: use fwnode_irq_get_byname instead of of_irq_get_byname to get irq

Not only platform devices described by OF have named interrupts, but
devices described by ACPI also have named interrupts. The fwnode is an
abstraction to different standards, and using fwnode_irq_get_byname can
support more devices.

Signed-off-by: Soha Jin <soha@lohu.info>
Tested-by: Wende Tan <twd2.me@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>