PCI: Remove the obsolete no_pci_devices() check

In function pci_get_subsys() there is a check:

	/*
	 * pci_find_subsys() can be called on the ide_setup() path,
	 * super-early in boot.  But the down_read() will enable local
	 * interrupts, which can cause some machines to crash.  So here we
	 * detect and flag that situation and bail out early.
	 */
	if (unlikely(no_pci_devices()))
		return NULL;

But there is no ide_setup() now, and no down_read() either, which
makes the check obsolete. So remove it.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>