irqchip/al-fic: make AL_FIC depend on HAS_IOMEM

On s390 systems (aka mainframes), it has classic channel devices for
networking and permanent storage that are currently even more common than
PCI devices.  Hence it could have a fully functional s390 kernel with
CONFIG_PCI=n, then the relevant iomem mapping functions [including
ioremap(), devm_ioremap(), etc.] are not available.

Here let AL_FIC depend on HAS_IOMEM so that it won't be built
to cause below compiling error if PCI is unset:

------
ld: drivers/irqchip/irq-al-fic.o: in function `al_fic_init_dt':
irq-al-fic.c:(.init.text+0x76): undefined reference to `of_iomap'
ld: irq-al-fic.c:(.init.text+0x4ce): undefined reference to `iounmap'
------

Link: https://lkml.kernel.org/r/[email protected]
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Signed-off-by: Baoquan He <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Marc Zyngier <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

drivers/irqchip/Kconfig

@@ -89,6 +89,7 @@ config ALPINE_MSI
 config AL_FIC
 	bool "Amazon's Annapurna Labs Fabric Interrupt Controller"
 	depends on OF
+	depends on HAS_IOMEM
 	select GENERIC_IRQ_CHIP
 	select IRQ_DOMAIN
 	help