lguest: replace hypercall name LHCALL_SET_PMD with LHCALL_SET_PGD

replace LHCALL_SET_PMD with LHCALL_SET_PGD hypercall name
(That's really what it is, and the confusion gets worse with PAE support)

Signed-off-by: Matias Zabaljauregui <zabaljauregui@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reported-by: Jeremy Fitzhardinge <jeremy@goop.org>
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c
index ffba723..6a54d76 100644
--- a/drivers/lguest/page_tables.c
+++ b/drivers/lguest/page_tables.c
@@ -568,7 +568,7 @@
  *
  * So with that in mind here's our code to to update a (top-level) PGD entry:
  */
-void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 idx)
+void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 idx)
 {
 	int pgdir;