xen/pvh: correctly setup the PV EFI interface for dom0

This involves initializing the boot params EFI related fields and the
efi global variable.

Without this fix a PVH dom0 doesn't detect when booted from EFI, and
thus doesn't support accessing any of the EFI related data.

Reported-by: PGNet Dev <pgnet.dev@gmail.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org # 4.19+
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 0e60bd9..2f111f4 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -122,9 +122,9 @@ static inline void __init xen_init_vga(const struct dom0_vga_console_info *info,
 void __init xen_init_apic(void);
 
 #ifdef CONFIG_XEN_EFI
-extern void xen_efi_init(void);
+extern void xen_efi_init(struct boot_params *boot_params);
 #else
-static inline void __init xen_efi_init(void)
+static inline void __init xen_efi_init(struct boot_params *boot_params)
 {
 }
 #endif