ixgbe: section fixes

ixgbe_init_interrupt_scheme() is called from ixgbe_resume().  Build that
with CONFIG_PM and without CONFIG_HOTPLUG and you've got a problem.
Several helpers called by it also are misannotated __devinit.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>