xen: grant: use xen_pfn_t type for frame_list.

This correctly sizes it as 64 bit on ARM but leaves it as unsigned
long on x86 (therefore no intended change on x86).

The long and ulong guest handles are now unused (and a bit dangerous)
so remove them.

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/arm/xen/grant-table.c

@@ -33,7 +33,7 @@
 #include <xen/page.h>
 #include <xen/grant_table.h>
 
-int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
+int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
 			   unsigned long max_nr_gframes,
 			   void **__shared)
 {