smc91x is shared between many different platforms.  Each platform needs
to specify the interrupt type, and in some cases the irq type depends
on more than just the build configuration - it depends on runtime
checks.

Rather than throwing this code into the SMC_IRQ_FLAGS definition, provide
a way for these flags to be passed via the IRQ resource itself.

Note that IRQF_TRIGGER_* constants are intentionally defined to correspond
with the IORESOURCE_IRQ_* interrupt type flags, in much the same way that
the low bits of PCI iomem resources correspond with the BAR flag bits.

Also provide a way to configure smc91x to read the IRQ flags from the
resource.  Once all platforms have been converted over (signified
by all definitions of SMC_IRQ_FLAGS being -1) SMC_IRQ_FLAGS should
be removed.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Nicolas Pitre <nico@cam.org>
Acked-by: Jeff Garzik <jgarzik@redhat.com>