[PATCH] Removed remaining PCI specific references from swiotlb.c

Matthew Wilcox pointed out that swiotlb.c implements a generic
interface that is not tied to just PCI.  Remove includes of
<linux/pci.h>, <asm/pci.h>.  Fix comments and printk() messages
to no longer refer to PCI.

Signed-off-by: Tony Luck <tony.luck@intel.com>