PCI: add debug output for DMA mask info

This allows us to find out what DMA mask is used for each PCI device at boot
time; useful for debugging.

After the patch:
ehci_hcd 0000:00:02.1: using 31bit consistent DMA mask
e1000 0000:0b:01.0: using 64bit DMA mask
e1000 0000:0b:01.0: using 64bit consistent DMA mask
e1000e 0000:04:00.0: using 64bit DMA mask
e1000e 0000:04:00.0: using 64bit consistent DMA mask
ixgb 0000:0c:01.0: using 64bit DMA mask
ixgb 0000:0c:01.0: using 64bit consistent DMA mask
aacraid 0000:86:00.0: using 32bit DMA mask
aacraid 0000:86:00.0: using 32bit consistent DMA mask
aacraid 0000:86:00.0: using 64bit DMA mask
aacraid 0000:86:00.0: using 64bit consistent DMA mask
qla2xxx 0000:0c:02.0: using 64bit consistent DMA mask
qla2xxx 0000:0c:02.1: using 64bit consistent DMA mask
lpfc 0000:06:00.0: using 64bit DMA mask
lpfc 0000:06:00.1: using 64bit DMA mask
pata_amd 0000:00:06.0: using 32bit DMA mask
pata_amd 0000:00:06.0: using 32bit consistent DMA mask
mptsas 0000:0c:04.0: using 64bit DMA mask
mptsas 0000:0c:04.0: using 64bit consistent DMA mask

forcedeth 0000:00:08.0: using 39bit DMA mask
forcedeth 0000:00:08.0: using 39bit consistent DMA mask
niu 0000:02:00.0: using 44bit DMA mask
niu 0000:02:00.0: using 44bit consistent DMA mask
sata_nv 0000:00:05.0: using 32bit DMA mask
sata_nv 0000:00:05.0: using 32bit consistent DMA mask
ib_mthca 0000:03:00.0: using 64bit DMA mask
ib_mthca 0000:03:00.0: using 64bit consistent DMA mask

Reviewed-by: Grant Grundler <grundler@google.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/pci.c

@@ -2101,6 +2101,7 @@ pci_set_dma_mask(struct pci_dev *dev, u64 mask)
 		return -EIO;
 
 	dev->dma_mask = mask;
+	dev_dbg(&dev->dev, "using %dbit DMA mask\n", fls64(mask));
 
 	return 0;
 }
@@ -2112,6 +2113,7 @@ pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask)
 		return -EIO;
 
 	dev->dev.coherent_dma_mask = mask;
+	dev_dbg(&dev->dev, "using %dbit consistent DMA mask\n", fls64(mask));
 
 	return 0;
 }