xen: sysfs: fix build warning.

Define PRI macros for xen_ulong_t and xen_pfn_t and use to fix:
drivers/xen/sys-hypervisor.c:288:4: warning: format '%lx' expects argument of type 'long unsigned int', but argument 3 has type 'xen_ulong_t' [-Wformat]

Ideally this would use PRIx64 on ARM but these (or equivalent) don't
seem to be available in the kernel.

Acked-by: Stefano Stabellini <[e-mail]>
Signed-off-by: Ian Campbell <[e-mail]>
Signed-off-by: Konrad Rzeszutek Wilk <[e-mail]>

arch/arm/include/asm/xen/interface.h

···
 /* Explicitly size integers that represent pfns in the interface with
  * Xen so that we can have one ABI that works for 32 and 64 bit guests. */
 typedef uint64_t xen_pfn_t;
+#define PRI_xen_pfn "llx"
 typedef uint64_t xen_ulong_t;
+#define PRI_xen_ulong "llx"
 /* Guest handles for primitive C types. */
 __DEFINE_GUEST_HANDLE(uchar, unsigned char);
 __DEFINE_GUEST_HANDLE(uint,  unsigned int);

arch/x86/include/asm/xen/interface.h

···
  * with Xen so that on ARM we can have one ABI that works for 32 and 64
  * bit guests. */
 typedef unsigned long xen_pfn_t;
+#define PRI_xen_pfn "lx"
 typedef unsigned long xen_ulong_t;
+#define PRI_xen_ulong "lx"
 /* Guest handles for primitive C types. */
 __DEFINE_GUEST_HANDLE(uchar, unsigned char);
 __DEFINE_GUEST_HANDLE(uint,  unsigned int);

drivers/xen/sys-hypervisor.c

···
 		ret = HYPERVISOR_xen_version(XENVER_platform_parameters,
 					     parms);
 		if (!ret)
-			ret = sprintf(buffer, "%lx\n", parms->virt_start);
+			ret = sprintf(buffer, "%"PRI_xen_ulong"\n",
+				      parms->virt_start);
 		kfree(parms);
 	}