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

This is the way x86_64 does, so this make them equal. They have
to be extern now in the header, and the extern definition is moved to
the common dma-mapping.h header.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/dma-mapping.h b/include/asm-x86/dma-mapping.h
index 51a79d7..c671a0a 100644
--- a/include/asm-x86/dma-mapping.h
+++ b/include/asm-x86/dma-mapping.h
@@ -62,6 +62,9 @@
 			 void *vaddr, dma_addr_t dma_handle);
 
 
+extern int dma_supported(struct device *hwdev, u64 mask);
+extern int dma_set_mask(struct device *dev, u64 mask);
+
 #ifdef CONFIG_X86_32
 # include "dma-mapping_32.h"
 #else