phys_to_pfn_t: use phys_addr_t

A dma_addr_t is potentially smaller than a phys_addr_t on some archs.
Don't truncate the address when doing the pfn conversion.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reported-by: Matthew Wilcox <willy@linux.intel.com>
[willy: fix pfn_t_to_phys as well]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

kernel/memremap.c

@@ -150,7 +150,7 @@ void devm_memunmap(struct device *dev, void *addr)
 }
 EXPORT_SYMBOL(devm_memunmap);
 
-pfn_t phys_to_pfn_t(dma_addr_t addr, unsigned long flags)
+pfn_t phys_to_pfn_t(phys_addr_t addr, unsigned long flags)
 {
 	return __pfn_to_pfn_t(addr >> PAGE_SHIFT, flags);
 }