x86: move dma_supported and dma_set_mask to pci-dma_32.c, fix

ERROR: "dma_supported" [drivers/ssb/ssb.ko] undefined!
ERROR: "dma_set_mask" [drivers/scsi/qla2xxx/qla2xxx.ko] undefined!
ERROR: "dma_set_mask" [drivers/scsi/aic7xxx/aic7xxx.ko] undefined!
ERROR: "dma_set_mask" [drivers/scsi/aic7xxx/aic79xx.ko] undefined!
ERROR: "dma_supported" [drivers/net/pcnet32.ko] undefined!
ERROR: "dma_supported" [drivers/media/video/saa7134/saa7134.ko] undefined!
ERROR: "dma_set_mask" [drivers/media/video/meye.ko] undefined!
ERROR: "dma_supported" [drivers/media/video/cx88/cx8802.ko] undefined!
ERROR: "dma_supported" [drivers/media/video/cx88/cx8800.ko] undefined!
ERROR: "dma_supported" [drivers/media/video/cx88/cx88-alsa.ko] undefined!
ERROR: "dma_supported" [drivers/media/video/cx23885/cx23885.ko] undefined!

They just need to be exported like on x86_64.

dma_supported() and dma_set_mask() were previously inlined,
but are now moved to pci-dma_32.c.

Since they're used by various drivers, they need to be
exported.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>