x86: fix set_fixmap to use phys_addr_t

Use phys_addr_t for receiving a physical address argument instead of
unsigned long.  This allows fixmap to handle pages higher than 4GB on
x86-32.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/xen/mmu.c

@@ -1750,7 +1750,7 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
 }
 #endif	/* CONFIG_X86_64 */
 
-static void xen_set_fixmap(unsigned idx, unsigned long phys, pgprot_t prot)
+static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
 {
 	pte_t pte;